JPH0224550B2 - - Google Patents

Description

BACKGROUND OF THE INVENTION Technical Field The present invention relates to a catheter guidewire that can guide a catheter, and is used to guide a therapeutic or testing catheter to a predetermined site such as a blood vessel, digestive tract, trachea, or other body cavity. This invention relates to a catheter guidewire that can be introduced and placed up to

BACKGROUND ART Conventionally, a coiled guidewire made of stainless steel wire or piano wire, or a monofilament-shaped guidewire made of plastic has been used as a guidewire for a catheter. All of the conventional guide wires mentioned above have a general metal material, such as stainless steel wire or piano wire, whose cross-sectional area gradually decreases from the main body toward the distal end in a part or the entire length of the guide wire. It has a main body with high rigidity and a relatively flexible tip.

The above-mentioned guide wire can be used to
It is inserted percutaneously into a blood vessel using an introducer needle, etc., and is used to insert the tip opening of the catheter into the end of the main body of the guide wire located outside the body, and insert the catheter into the blood vessel with the guide wire as the axis. There are many things. Therefore, the above-mentioned guide wire can be smoothly inserted into a blood vessel against the resistance generated between the outer surface of the guide wire and the tissue, and also resists the resistance generated between the outer surface of the guide wire and the inner surface of the catheter. A certain degree of rigidity is provided to the main body so that the catheter can be guided.

However, as mentioned above, the main body of the conventional guidewire is made of a general metal material, and if the displacement exceeds a certain level, plastic deformation occurs.
Hand manipulation may cause the guidewire to buckle, resulting in the buckled part becoming irreversibly deformed, and this deformed part becomes a large resistance to catheter advancement, causing catheter failure. This causes difficulty in smooth installation operations. In addition, when guiding a catheter with the distal end curved in advance to facilitate insertion into a predetermined vascular site,
Since the catheter is inserted into the guidewire and straightened, the resistance to insertion of the catheter into the guidewire increases, increasing the possibility of trouble occurring due to the buckling.

In addition, after the catheter is inserted into the blood vessel together with the guide wire, the distal end of the guide wire, which protrudes by a predetermined length from the distal opening of the catheter, is further inserted into the blood vessel in order to reach a predetermined vascular site. We need to get ahead and push forward. Therefore, the tip of a conventional guidewire is required to have flexibility so that it does not damage the blood vessel wall, has good shape adaptability even in tortuous blood vessels, and can be inserted into complicated blood vessel branches.

However, as mentioned above, the tip of the conventional guidewire is made of a general metal material or plastic, and when the displacement exceeds a certain level, plastic deformation occurs, resulting in flexible vascular travel to a predetermined vascular site. In addition, even if the tip of the guide wire reaches the specified blood vessel site, the tip has reduced rebound resilience due to plastic deformation, so when advancing the tip of the catheter, There is no resistance between the guidewire tip and the vessel wall necessary to keep the guidewire tip in place against the bending stress of the catheter, and as a result, the guidewire tip can be pulled away from a given vascular site. This often results in the part being pulled out, failing to place it in the correct location, and requiring a large amount of procedure time. In addition, in order to prevent damage to the blood vessel wall and snags while running inside the blood vessel, some guidewires have their distal ends deformed into a J-shape. Since they are always deformed into a straight line, many of them do not restore to a perfect J-shape within the blood vessel and do not fully demonstrate their initial function.

Further, the guide wire shall have an outer diameter approximately equal to the inner diameter of the catheter so that the catheter guided by the guide wire can easily and smoothly expand the skin wall and blood vessel wall. is desirable. In addition, since blood leaks from the gap between the guide wire and the introducer needle when inserting the guide wire into the introducer needle, the distal end should have an outer diameter that is approximately the same as the inner diameter of the introducer needle, that is, an outer diameter that is the same as the main body. desirable. Therefore, in the case of the above-mentioned guide wire, the outer diameter is approximately equal to the inner diameter of the distal end of the catheter to be guided, and even if the outer diameter increases as a result, each of the main body and the distal end It is desirable to have the necessary elastic strain characteristics.

OBJECTS OF THE INVENTION An object of the present invention is to provide a catheter guide wire that allows a catheter to be introduced into a predetermined site reliably and easily.

More specifically, the object is to provide a guidewire whose main body does not buckle during insertion and crown insertion.

Furthermore, even if it buckles, it will return to its original state,
The purpose of the present invention is to provide a guidewire that does not affect insertion and crown insertion resistance.

A further object of the present invention is to provide a guidewire whose distal end has the flexibility to be inserted into complicated blood vessels and has good resilience against deformation.

Furthermore, the tip always has a moderate repulsion elasticity,
It is an object of the present invention to provide a guide wire whose tip remains in place when guiding the catheter.

Furthermore, in guide wires of various outer diameters,
The object is to provide guidewires having substantially the same physical properties.

Structure of the Invention The present invention provides a catheter guide wire in which an inner core is formed by a main body side inner core part and a distal end side inner core part, and the inner core is almost entirely covered with a covering part. , at least one of the main body inner core and the distal inner core is formed of a superelastic metal body, and the cross-sectional area of at least a part of the distal inner core is the same as the cross-sectional area of the main body inner core. small compared to
Furthermore, the outer diameter of the tip of the covering portion is smaller than that of the main body portion in accordance with the surface of the inner core.

According to the present invention, the following effects are achieved.

This is due to the fact that the main body inner core is made of a superelastic metal body, and the cross sectional area of the main body inner core is larger than the cross sectional area of at least a portion of the distal inner core. Therefore, the main body portion can be provided with elastic strain characteristics having relatively high buckling strength. This means that it is possible to realize a guidewire in which the 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.

This is due to the fact that the distal inner core is formed of a superelastic metal body, and the cross-sectional area of at least a portion of the distal inner core is smaller than the cross-sectional area of the main body inner core. Therefore, the tip portion can be provided with elastic strain characteristics that can be deformed relatively largely under a constant stress and can be restored. This means that the tip 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., and that it can be inserted into a predetermined site such as a blood vessel. This means that it is possible to create a guidewire with the appropriate repulsion resilience required for this purpose.

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is a plan view showing a catheter guide wire 10 according to an embodiment of the present invention, and FIGS. 2 to 4 are cross-sectional views taken along lines - to - in FIG. 1. be.

The guide wire 10 includes an inner core 11 and a covering portion 12, and forms a main body portion 10A and a distal end portion 10B.

The inner core 11 of the guide wire 10 has a main body side inner core part 11A and a distal end side inner core part 11B connected to a tapered part 1.
It is integrated through 1C, and the whole is 49-58
TiNi alloy with atomic% Ni, 38.5-41.5 wt% Zn Cu
-Zn alloy, 1-10% by weight of Cu-Zn-X alloy (X = Be, Si, Sn, Al, Ga), 36-38 atomic% of Al
It is made of a superelastic (pseudoelastic) metal body such as Ni-Al alloy.

Further, the covering portion 12 of the guide wire 10 is
It consists of a main body side covering part 12A and a tip side covering part 12B, and is made of synthetic resin such as polyethylene, polyvinyl chloride, polyester, polypropylene, polyamide, polyurethane, polystyrene, fluorine resin, silicone rubber, or each elastomer and composite material. It is flexible and forms a smooth surface with no irregularities. Note that the covering portion 12 is
Anticoagulant properties can be obtained by coating with anticoagulants such as heparin and urokinase, or antithrombotic materials such as silicone rubber, urethane and silicone block copolymers (Abcosan), and hydroxyethyl methacrylate-styrene copolymers. It is possible to obtain low friction properties by using a resin having a low friction surface such as a fluororesin and by applying a lubricant such as silicone oil. In addition, Ba,
By mixing an X-ray contrast agent made of a single metal or a compound such as W, Bi, or Pb, it becomes possible to accurately confirm the position of the guide wire 10 within the blood vessel.

The main body part 10A of the guide wire 10 has an outer diameter of 0.62 mm for the main body side inner core part 11A and a main body side covering part 12A.
The outer diameter is 0.89 mm, the length is 130 cm, and the yield stress (yield stress under load: A in Figure 8) is 10 to 80 Kg/mm ² (22
°C), restoring stress (yield stress at unloading: B in Figure 8)
is set at 0 to 60 Kg/mm ² (22°C). The outer diameter of the inner core portion 11A on the main body side is set in the range of 0.1 to 1.9 mm, more preferably 0.35 to 1.05 mm, to improve buckling strength.
10~80Kg/mm ² (22℃), restoring stress 0~60Kg/mm ²
(22℃). In addition, the main body side covering part 1
The outer diameter of 2A is 0.2 to 2 mm, more preferably 0.45
It is best to set it within the range of ~1.15mm. Further, the length of the main body portion 10A is preferably set in a range of 10 to 300 cm.

The distal end portion 10B of the guide wire 10 has a distal inner core portion 11b with an outer diameter of 0.2 mm and a distal covering portion 12B.
The outer diameter is 0.47 mm, the length is 0 to 150 mm, preferably 2 to 150 mm, more preferably 20 mm, and the yield stress is
10~80Kg/mm ² (22℃), restoring stress 0~60Kg/mm ²
(22℃). In addition, the tip side inner core part 11B
The outer diameter of is 0.05 to 1.5 mm, more preferably 0.1 to 1.5 mm.
It is preferable that the bending load is set in the range of 0.5 mm, the bending load is 0.1 to 10 g, and the restoring load is 0.1 to 10 g. Further, the outer diameter of the inner core part on the distal end side does not have to be all the above-mentioned dimensions, but may be a part of the outer diameter. Furthermore, the restoring stresses of the main body and the tip do not need to have the same value; rather, it is preferable to change them depending on the heat treatment conditions so as to obtain appropriate physical properties at an appropriate wire diameter. That is, it is preferable to separate the heat treatment of the main body and the tip so that the main body has a large restoring stress and the tip becomes flexible. Therefore, the strength can be increased without making the wire diameter of the inner core on the tip side too thin. Further, the outer diameter of the distal end side covering portion 12B is 0.07 to 2 mm, more preferably 0.12 to 2 mm.
It is best to set it within the range of 1.10mm. Further, the outer diameter of the tip portion including the covering portion does not have to be entirely the above-mentioned size, but may be a portion thereof. In addition, the tip 1
The length of 0B is preferably set in a range of 1 to 50 cm. Further, it is preferable that the outer diameter of the covering portion is equal to that of the tip portion and the main body portion.

Further, the covering portion 12 is usually melt-molded from the synthetic resin body to be in close contact with the inner core 11, and also includes the distal end portion 13 and the guide wire 1.
Similarly, it is fixed on the side opposite to the distal end, that is, the proximal end 16 of 0. However, when the covering part 12 is formed of a hollow tube, in addition to the form in which the covering part 12 is tightly covered over the entire length, it is also possible to cover the distal end part 13 and the proximal end part 16 of the guide wire 10 or the appropriate part of the main body part. It is also preferable that the inner core 11 be fixed to the inner core 11 by adhesive or melt molding. In this case, the distal end portion 13 and the proximal end portion 16 or a suitable portion of the main body are adhesively bonded to the inner core 11 over substantially the entire length. , or is not fixed, and therefore, when the guide wire 10 is bent, it is not restrained by the inner core 11 and can freely move relative to the inner core 11, especially when the tip part 10B of the guide wire 10 is flexible. It allows for transformation. The covering portion in the present invention may be one in which the surface of the inner core 11 is coated with a coating thin film made of the aforementioned synthetic resin material. Also in this case, it is preferable that the covering portion is not fixed to at least the distal inner core portion 11B, so that the distal end portion 10B of the guide wire 10 can be deformed more flexibly. In the guidewire of the present invention, the manner in which the inner core and the covering portion are fixed is not particularly limited.

The most distal end 1 of the distal end 10B of the guide wire 10
3 has an R shape to prevent penetration into the blood vessel wall. Further, the tapered portion 11C has its cross-sectional area continuously reduced from the main body portion 10A to the distal end portion 10B, so that the rigidity changes gradually at the connection portion between the main body portion 10A and the distal end portion 10B,
This makes it possible to prevent the guide wire 10 from bending at the connection portion.

Note that the most distal end of the distal end portion 10B of the guide wire 10 is not necessarily rounded, but as shown in FIG. 5A.
It may be spherical as shown in FIG. 5, or J-shaped as shown at 15 in FIG. 5B to prevent penetration into the blood vessel wall.

In addition, as shown in FIGS. 6A and 6B, the guide wire 10 has its distal end 10B curved into a predetermined shape similar to a blood vessel running or branching, thereby ensuring insertion into a predetermined vascular site. And it can be done easily.

Further, the guide wire 10 has a distal end portion 10B.
By making the diameter gradually smaller toward the most distal end 13, it is possible to make the distal end 10B more flexible.

Moreover, the main body portion 10A in the guide wire 10
The connecting portion between the main body portion 10A and the distal end portion 10B is not necessarily tapered, but may have a cross-sectional shape that does not cause a significant change in cross-sectional area between the main body portion 10A and the distal end portion 10B. Part 10A
It may have an outer diameter intermediate between the tip portion 10B and the tip portion 10B.

In addition, the inner core is not limited to being composed of a single wire, but may also be composed of multiple wires in parallel or twisted, which exhibit the above-mentioned function, that is, a gradual or continuous change in physical properties. good.

Figure 7 shows a cover made of polyethylene with an outer diameter of 0.89 mm, an outer diameter of 0.62 mm, and a length of 20 mm.
The solid line shows the bending load (W) vs. displacement (D) characteristics of the TiNi alloy that forms the cantilever beam.
It is a diagram showing, by broken lines, the bending load-displacement characteristics of a stainless steel wire that is covered with a covering section made of 0.89 mm polyethylene and forms a cantilever beam with an outer diameter of 0.45 mm and a length of 20 mm. Figure 8 shows the outer diameter
The solid line shows the bending load-displacement characteristics of a TiNi alloy that is covered with a 0.42 mm polyethylene coating and forms a cantilever beam with an outer diameter of 0.15 mm and a length of 20 mm. Covered with a polyethylene covering part, outer diameter 0.10mm, length 20mm.
FIG. 3 is a diagram showing, by broken lines, the bending load-displacement characteristics of a stainless steel wire forming a cantilever beam of cm. In addition, in FIGS. 7 and 8, E is
This is the amount of plastic residual strain in stainless steel wire. In other words, according to Figures 7 and 8, a superelastic metal body has the following characteristics: (1) the recoverable elastic strain is large, and (2) the magnitude of the load does not change even if the strain increases. have. Therefore, the guide wire 10 has the following characteristics:
Since the main body part 10A is formed by the superelastic metal inner core part 11A and the synthetic resin covering part 12A, which have bending load-displacement characteristics that are approximately the same as the solid line in FIG. The main body portion 10A has elastic strain characteristics with relatively high buckling strength. Further, the guide wire 10 has an inner core portion 11B made of a superelastic metal body and a sheathing portion 12B made of a synthetic resin body, which have bending load-displacement characteristics that are approximately the same as the solid line in FIG. As a result, the distal end portion 10B has an elastic strain characteristic that allows a relatively large displacement and restoration under a constant stress.

Figure 9 shows the bending rigidity (B) of a guide wire in which the superelastic metal inner core is covered with a synthetic resin coating.
FIG. 2 is a diagram in which the maximum outer diameter (G) characteristic is shown by a solid line, and the bending rigidity-maximum outer diameter characteristic of a guide wire made only of a superelastic metal body is shown by a broken line. This ninth
According to the figure, in the case of a guide wire made only of a superelastic metal body, the maximum outer diameter width (Δg1) that satisfies the set bending rigidity B1 to B2 is small, whereas
As in the guidewire 10 above, the inner core 11
By covering the outer diameter with the covering portion 12, the width of the maximum outer diameter (Δg2) that satisfies the set bending stiffness becomes very wide, and when the inner diameter of the catheter to be guided becomes large, the bending stiffness can be kept within a certain range. It is recognized that it is possible to form the main body portion 10A with a thickness substantially equal to the inner diameter of the catheter.

Specific action of the invention Next, the operation of the above embodiment will be explained.

As shown in FIG. 9, the guide wire 10 has a curved portion of various shapes formed at the distal end of the catheter 20, which is straightened under insertion of the relatively rigid body portion 11. Blood vessels 2
1 can proceed smoothly. Further, the guide wire 10 has a distal end portion 12
B in advance of the distal end of the catheter 20,
This allows the tip of the catheter 20 to be guided to a predetermined vascular site 22.

By covering the inner core 11 with the covering portion 12, the guide wire 10 can be used even when the catheter to be guided has a large diameter.
The diameter of the catheter is relatively small, the bending stiffness is kept within a certain range, and the outer diameter is matched to the inner diameter of the catheter to be guided, allowing the catheter to expand the skin and blood vessel walls effortlessly and smoothly. .

Further, in the guide wire 10, the cross-sectional areas of the distal inner core portion 11B and the distal tip covering portion 12B are smaller than the cross-sectional areas of the main body inner core portion 11A and the main body side covering portion 12A, respectively. Accordingly, the tip 10
B has a cross-sectional area smaller than that of the main body 10A, the main body 10A has an elastic strain characteristic with a relatively large buckling strength, and the tip 10B has a relatively large buckling strength under a constant stress. This makes it possible to have elastic strain characteristics that allow for large displacements and restoration.

That is, 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 10A
Even if a relatively large bending deformation occurs in the main body portion 10A, it does not reach the plastic deformation region and buckle.
It becomes possible to improve the buckling limit of That is, even if the main body portion 10A is significantly deformed due to a manual operation applied to the guide wire 10, the deformed portion easily returns to its straight state and does not become a resistance to the advancement of the catheter. Further, even when a catheter having a curved portion at the tip is inserted into the crown while being straightened, the main body 10A allows the catheter to advance smoothly without creating a large resistance between the catheter and the catheter. .

Further, the guide wire 10 has a distal end portion 10B.
It has elastic strain characteristics that allow it to undergo relatively large displacement under constant stress and to be able to recover. Therefore,
When the distal end portion 10B moves through the bend of the blood vessel, it easily undergoes large bending deformation under a relatively small load, and without damaging the blood vessel wall, bends and deforms in response to changes in the bend of the blood vessel, and restores the bending deformation. By repeating this process, it has good shape adaptability to tortuous blood vessels, can be curved relatively easily to blood vessel branches, and can be smoothly advanced to a predetermined blood vessel site. In addition, when inserting the catheter into a predetermined blood vessel site, the distal end should have sufficient rebound resilience to create the resistance against the blood vessel wall necessary to resist the bending stress of the catheter and remain in the predetermined position.
In preparation for 0B, the catheter can be appropriately indwelled without the distal end portion 10B being pulled out from a predetermined blood vessel site. Furthermore, even if the distal end portion 12, which has been curved in advance, is deformed into a straight line when passing through the introducer needle, it will be restored to its completely curved shape upon subsequent insertion into the blood vessel, and the initial function will be fully satisfied. possible. The guidewire 10 also has increased tensile strength and is safer than conventional plastic guidewires.

Further, unlike conventional coiled guide wires, the guide wire 10 has good torque transmittance in both torsional directions, and the main body 10
By applying the torque to A, the distal end 10B can be reliably and easily directed toward a predetermined blood vessel site,
Easy to insert into complex blood vessel sites.

In addition, in the above embodiment, the main body part 10A and the tip part 1
The guide wire 10 in which both the 0B and 0B are made of a superelastic metal body has been described. However, in the present invention, only the main body of the guide wire may be formed of a superelastic metal body, and the main body may be provided with elastic strain characteristics having relatively high buckling strength. Only the tip portion may be formed of a superelastic metal body, and the tip portion may be provided with an elastic strain characteristic that allows a relatively large displacement under a constant stress and allows recovery.

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

Effects of the Invention As described above, according to the present invention, the main body side inner core portion is formed of a superelastic metal body, and the cross-sectional area of the main body side inner core portion is at least a portion of the distal side inner core portion. The guidewire has a large cross-sectional area compared to the guidewire, so that the main body is difficult to buckle or twist when operated at hand, and even if buckling or twisting occurs, it can be easily restored to its original shape, facilitating smooth introduction operations. can be obtained. Further, by forming the distal inner core part from a superelastic metal body and making at least a part of the cross-sectional area of the distal inner core part smaller than the cross-sectional area of the main body inner core part. , the tip 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 the tortuous blood vessel, etc., and has sufficient flexibility and resilience to deformation to allow it to be inserted into a predetermined site such as a blood vessel. A guidewire with appropriate resilience can be obtained.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a catheter guide wire according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line - in FIG. 1, and FIG. 3 is a sectional view taken along the line - in FIG. 1. , FIG. 4 is a sectional view taken along the - line in FIG. 7 and 8 are diagrams showing the bending load-displacement characteristics of a superelastic metal body and a general elastic metal body, and FIG. FIG. 10 is a diagram showing the bending rigidity-maximum outer diameter characteristic of the guide wire, and is a schematic diagram showing the usage state of the guide wire according to the present invention. 11... Inner core, 11A... Main body side inner core part, 11B...
Distal end inner core part, 11C...Tapered part, 12...Coating part, 12A...Main body side coating part, 12B...Distal side coating part, 13...Distal end part, 16...Proximal end 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. , at least one of the main body inner core and the distal inner core is formed of a superelastic metal body, and the cross-sectional area of at least a part of the distal inner core is the same as the cross-sectional area of the main body inner core. be smaller than that, and further,
A guide wire for a catheter, wherein the outer diameter of the distal end of the covering portion is smaller than that of the main body portion in accordance with the surface of the inner core. 2. The guide wire for a catheter according to claim 1, wherein the cross-sectional area between the main body side inner core portion and the distal side inner core portion is continuously reduced from the main body portion toward the distal end portion. 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.