JP4828117B2 - Guide wire - Google Patents

Description

  The present invention relates to a guide wire, and particularly to a guide wire used when a catheter is introduced into a body cavity such as a blood vessel.

The guide wire can be used for the treatment of a site where surgical operation is difficult, such as PTCA (Percutaneous Transluminal Coronary Angioplasty), or for the purpose of minimally invasive to the human body, Used to guide catheters used for examinations such as angiography. A guide wire used for PTCA surgery is inserted to the vicinity of the target vascular stenosis portion together with the balloon catheter with the tip of the guide wire protruding from the tip of the balloon catheter. Guide to near.
The blood vessel is intricately curved, and the guide wire used to insert the balloon catheter into the blood vessel has flexibility and resilience to moderate bending, and pushability to transmit the operation at the proximal end to the distal side. In addition, torque transmission, kink resistance (bending resistance), and the like are required. Of these characteristics, a material having a relatively high elastic modulus such as stainless steel is often used in order to obtain an appropriate indentability and torque transmission (see, for example, Patent Document 1).
For example, in a PTCA guide wire, conventionally, a guide wire having an outer diameter of 0.014 inch (about 0.35 mm) has been used as a general size. In such an outer diameter guide wire, a material such as stainless steel can be used to obtain an appropriate pushability and torque transmission property, but a smaller diameter guide wire is required to reach a peripheral blood vessel. In some cases, conventional materials were not always satisfactory.

In addition, a stent, which is an example of an implantable treatment instrument, is a cylindrical medical instrument that is implanted to expand a stenosis that has occurred in a blood vessel or the like. For example, when it is expanded with a balloon and embedded in the inner wall of the blood vessel, it is made of a material having a relatively high elastic modulus, such as stainless steel, in order to obtain an expansion force.
Even with the same material, in order to obtain a larger expansion force, it can also be achieved by increasing the thickness of the cylindrical body. However, in order to obtain a high opening ratio of the vascular stenosis, a thinner stent has been desired. In addition, when a resin carrying a drug is coated on the stent surface, it becomes thicker due to the coating. Therefore, a material capable of obtaining an expansion force equivalent to or higher than that of the conventional one while reducing the thickness of the cylinder itself is desired. It was rare.

Japanese Patent Laid-Open No. 10-118055

An object of the present invention is to provide a guide wire capable of obtaining appropriate pushability and torque transmission.
An object of the present invention is to provide an implantable therapeutic device capable of obtaining an appropriate expansion force.

Such an object is achieved by the following invention (1) .
(1) A guide wire comprising a first wire arranged on the distal end side and a second wire joined to the proximal end side of the first wire, wherein the first wire is made of a Ni—Ti alloy. And the second wire is made of a material containing a Ni3Al intermetallic compound.
(2) The guide wire according to (1), wherein the material is a Ni3Al phase represented by a binary equilibrium diagram and includes 25.0 to 26.5 at% of Al with Ni as a main component at 400 ° C. or lower.
(3) The guide wire according to (1), wherein the material is a Ni3Al phase + Ni phase represented by a binary equilibrium diagram and includes 7.2 to 25.0 at% of Al with Ni as a main component at 400 ° C. or lower. .
(4) The guide wire according to (3), wherein the material includes a Ni3Al phase as a matrix and a Ni phase as an island.
(5) The guide wire according to (1), wherein the material is a Ni3Al phase + Ni5Al3 phase represented by a binary equilibrium diagram and includes 26.5 to 32.0 at% of Al containing Ni as a main component at 400 ° C. or lower. .
(6) The guide wire according to (1), wherein the material is made of a material made of a Ni3Al phase having an L12 type regular structure.
(7) The guide wire according to (6), wherein the Ni3Al phase exhibits spreadability at room temperature.
(8) The guide wire according to (7), wherein the Ni3Al phase is polycrystalline.
(9) The guide wire according to any one of (6) to (8), wherein the Ni3Al phase is a material that can substantially exhibit superplastic deformation.
(10) The guide wire according to (8), wherein the Ni3Al phase is added with a third element for the purpose of suppressing grain boundary fracture.
(11) The guide wire according to (10), wherein the third element is boron.
(12) The guide wire according to (10) or (11), wherein the content of the third element is 1 at% or less.
(13) The guide wire according to (8), wherein at least a part of the Ni3Al phase is substituted with a third element.
(14) The guide wire according to (13), wherein the third element is at least one selected from Ti, Ta, and Cu.
(15) The guide wire according to (14), wherein the Ti content is 0 to 10 at%.
(16) The guide wire according to (14), wherein the Ta content is 0 to 5 at%.
(17) The guide wire according to (14), wherein the Cu content is 0 to 10 at%.
(18) A cylindrical body having both ends opened and extending in the longitudinal direction between the both ends, and the cylindrical body is made of a material containing a Ni3Al intermetallic compound. Type treatment instrument.
(19) The side surface of the cylindrical body has a large number of notches communicating with the outer side surface and the inner side surface, and the notch portions can be deformed to expand and contract in the radial direction of the cylindrical body (18) The implantable therapeutic device according to 1.

  According to the guide wire of the present invention, moderate pushability and torque transmission can be obtained. Further, according to the implantable therapeutic device of the present invention, an appropriate expansion force can be obtained even if it is relatively thin.

Hereinafter, the guide wire of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
FIG. 1 is a longitudinal sectional view showing an embodiment of the guide wire of the present invention. A guide wire 1 shown in FIG. 1 is a guide wire for a catheter used by being inserted into a catheter, and includes a core member 3 and a spiral coil 5 provided on the distal end side of the core member 3. . The total length of the guide wire 1 is not particularly limited, but is preferably 1700 to 3000 mm.
The core material 3 is a wire made of a material to be described later, and includes a main body portion 33, a tapered portion 32 that is formed on the distal end side of the main body portion 33, and whose outer diameter gradually decreases in the distal direction, and a tapered portion. 32 and a small-diameter portion 31 having an outer diameter smaller than that of the main body portion 33.
The small-diameter portion 31 is formed at a first portion 311 having a substantially constant outer diameter along the longitudinal direction and a proximal end side of the first portion 311, and a second portion having a substantially constant outer diameter along the longitudinal direction. The portion 312 is formed between the first portion 311 and the first portion 311, and is formed between the first portion 311 and the second portion 312, and the tapered portion 313 whose outer diameter gradually decreases in the distal direction. And a tapered portion 314 whose outer diameter gradually decreases in the direction. The small diameter portion 31 is inserted through a substantially central portion inside the coil 5. The small diameter portion 31 is inserted in a non-contact manner with the inner surface of the coil 5.
Since the core material 3 has the taper portion 313, the taper portion 314, and the taper portion 32, the rigidity of the core material 3 can be gradually decreased toward the distal end direction. In addition, it is possible to obtain good flexibility, improve followability to blood vessels and safety, and prevent bending and the like.
Further, in the present embodiment, since the main body 33 having a larger outer diameter and higher rigidity than the small diameter portion 31 is formed, a force transmitted from the hand, for example, a force such as torque or pushing, is applied to the main body 33. Therefore, it is reliably transmitted to the small diameter portion 31, and thus excellent insertion operability is obtained. Although the length of the main-body part 33 is not specifically limited, 200-5000 mm is preferable. Moreover, the outer diameter of the main-body part 33 is although it does not specifically limit, 0.2-1.2 mm is preferable.

Core 3 is made of a material containing Ni ₃ Al intermetallic compound. Such materials are illustrated by means of a two-phase equilibrium diagram of a nickel FIG 2 (Ni) and aluminum (Al) (Binary Alloy Phase Diagrams 2 nd edition Vol.1,1990, P183). The material of the core material 3 is a Ni ₃ Al phase (represented as “AlNi ₃ ” in FIG. 2) shown in a binary equilibrium diagram as shown in FIG. (Ni) 73.5-75at% is contained. That is, it contains 25.0 to 26.5 at% of aluminum (Al).
The core material 3 made of a material containing a Ni ₃ Al intermetallic compound has a relatively wide elastic range and a high yield stress. The elastic region of the core material 3 has, for example, 5 to 10%. The yield stress of the core material 3 is, for example, 1300 to 2200 MPa. Furthermore, the elastic modulus of the core material 3 is, for example, 200 to 350 MPa. Since the core material 3 has a high elastic deformability as a wire, it is difficult to be plastically deformed even if the diameter is reduced. When the guide wire itself is pushed forward or when the guide wire is advanced along the guide wire, if the guide wire is subjected to a bending force, it has a high yield stress, so it resists a certain amount of bending force. be able to. Moreover, since it has a wide elastic region, it can return to its original shape when the force is lost. These characteristics are particularly effective in the case of a guide wire having a reduced diameter (for example, an outer diameter of about 0.254 mm). Therefore, even if the guide wire has a particularly small diameter, an appropriate pushability can be obtained. Furthermore, the touch of the leading edge of the guide wire touching the blood vessel wall or stenosis can be felt at hand.

  Also, when torque is applied by twisting the hand of a guide wire inserted into a significantly bent blood vessel, if the plastic deformation occurs along the bent blood vessel, the torque becomes extremely difficult to be transmitted and the tip is directed in a desired direction. I cannot expect subtle operations. Since the core material 3 of the present embodiment has high elastic deformability, when the hand of the guide wire curved along the blood vessel is twisted, the torque is transmitted to the tip, and a delicate operation for turning the tip in a desired direction becomes possible. . Thus, good torque transmission can be obtained even in such a tortuous blood vessel.

  Further, the material of the core 3 is different from a material having a high elastic modulus and yield point, such as ceramics or precipitation hardening metal material, and the yield point and the break point are substantially separated. It has the property of plastic deformation. If the surgeon operating the guide wire has applied stresses that exceed the elastic deformation capability of the wire, destruction must be avoided. This is because the sharp fracture surface may destroy the body tissue. For this reason, when the wire elastic deformation capability is exceeded, it is desirable to provide an indicator function that appropriately plastically deforms and notifies the operator of the abnormality. A material that undergoes brittle fracture does not have an indicator function because yield (end of elastic deformation) and fracture substantially coincide. On the other hand, the above-mentioned material having a wide elastic range and a high yield point has the property of being plastically deformed after yield because the yield point and the break point are substantially separated. That is, the above material is a material having an indicator function for notifying the operation limit.

  Next, it is preferable that the main body portion 33 of the core member 3 is subjected to a process for suppressing friction generated by contact with the inner wall of the catheter used together with the guide wire 1. As this process, in this embodiment, the surface of the main body 33 that contacts the inner wall of the catheter is made of a substance having a low friction coefficient with respect to the material of the inner wall of the catheter (for example, a fluorine resin such as polytetrafluoroethylene, silicone, etc.). A structured coating layer 7 is provided. Thereby, friction with a catheter inner wall is suppressed and the operativity of the core material 3 in a catheter becomes a better thing.

The coil 5 is preferably made of a metal material. Examples of the metal material constituting the coil 5 include superelastic alloys such as stainless steel and Ni—Ti alloys, shape memory alloys, cobalt alloys, noble metals such as gold, platinum, and tungsten, or alloys containing the same. Is mentioned. In particular, when the guide wire 1 is made of an X-ray opaque material such as a noble metal, X-ray contrast can be obtained in the guide wire 1, and the guide wire 1 can be inserted into the living body while confirming the position of the tip under X-ray fluoroscopy. It is possible and preferable. You may comprise at least one part of the coil 5 with the material of the core material 3 mentioned above. Moreover, you may comprise the coil 5 with the material from which the front end side and base end side differ. For example, the distal end side may be constituted by a coil made of an X-ray opaque material, and the proximal end side may be constituted by a coil made of a material (such as stainless steel) that relatively transmits X-rays. The total length of the coil 5 is not particularly limited, but is preferably 100 to 500 mm.
The proximal end portion of the coil 5 is fixed to the tapered portion 32 of the core material 3 by the fixing material 11, and the intermediate portion of the coil 5 is fixed to the first portion 311 or the tapered portion 313 of the core material 3 by the fixing material 12. The distal end portion of the coil 5 is fixed to the distal end portion of the first portion 311 by the fixing material 13. The fixing materials 11, 12 and 13 are made of, for example, solder (brazing material). These fixing methods are not limited to those using a fixing material, and other fixing methods include welding, adhesion using an adhesive, and the like. In order to prevent damage to the inner wall of the blood vessel, the distal end surface of the fixing material 13 is preferably rounded.

  In addition, although this embodiment is an example which used the material mentioned above for the core material 3, the core material 3 is comprised with materials, such as stainless steel and a cobalt base alloy, and at least one part of the coil 5 is made into the material mentioned above. Embodiments configured as described above are also possible. Even if the coil wire is thinned due to the wide elastic range and high yield point of the material, an extremely supple coil can be provided, and the guide wire provided with the coil can be reduced in diameter. In the case of the present embodiment, the coil 5 has a circular cross section of the wire. However, the present invention is not limited to this, and the cross section of the wire is, for example, elliptical or quadrangular (particularly rectangular). Also good.

The entire surface (particularly the outer surface) of the coil 5 is preferably entirely or partially covered with a coating (not shown) made of a hydrophilic material or a hydrophobic material. Thereby, the guide wire 1 can be inserted more smoothly.
Examples of the hydrophilic material constituting the coating include cellulose-based polymer materials, polyethylene oxide-based polymer materials, and maleic anhydride-based polymer materials (for example, maleic anhydride such as methyl vinyl ether-maleic anhydride copolymer). Copolymer), acrylamide polymer (for example, polyacrylamide, polyglycidyl methacrylate-dimethylacrylamide (PGMA-DMAA) block copolymer), water-soluble nylon, polyvinyl alcohol and the like. Moreover, as a hydrophobic material which comprises a film, fluororesins, such as polytetrafluoroethylene, a silicone type material, etc. are mentioned, for example.

Next, another embodiment of the guide wire of the present invention will be described. Structurally, it is the same as the guide wire shown in FIG. 1, and the core material 3 is an elastic wire, and is formed on the main body portion 33 and the front end side of the main body portion 33, and has an outer diameter in the front end direction. Has a tapered portion 32 that gradually decreases, and a small-diameter portion 31 that is formed on the distal end side of the tapered portion 32 and has a smaller outer diameter than the main body portion 33.

Core member 3 of the present embodiment is constituted of a material containing Ni ₃ Al intermetallic compound. This material is a Ni ₃ Al phase + Ni phase represented by a binary equilibrium diagram as shown in FIG. 2 and contains 7.2 to 25.0 at% Al with Ni as the main component at 400 ° C. or lower. Further, this material has a Ni ₃ Al phase as a matrix and a Ni phase as an island. The material is made of Ni ₃ Al phase as a matrix and Ni phase as an island, so it has high yield stress but has a relatively wide elastic range.
The core material 3 of the present embodiment is a Ni ₃ Al phase + Ni ₅ Al ₃ phase represented by a binary equilibrium diagram as shown in FIG. 2, and is composed mainly of Ni at 400 ° C. or lower. A material containing 26.5 to 32.0 at% may be used.

  Next, still another embodiment of the guide wire of the present invention will be described. Structurally, it is the same as the guide wire shown in FIG. 1, and the core material 3 is an elastic wire, and is formed on the main body portion 33 and the front end side of the main body portion 33, and has an outer diameter in the front end direction. Has a tapered portion 32 that gradually decreases, and a small-diameter portion 31 that is formed on the distal end side of the tapered portion 32 and has a smaller outer diameter than the main body portion 33.

Core 3 is made of a material consisting of Ni ₃ Al phase having an L1 ₂ ordered structure. The Ni ₃ Al phase is desirably a material that can substantially exhibit superplastic deformation. In order to substantially exhibit superplastic deformation, for example, it can be achieved by making the crystal grains about 10 μm or less.
The Ni ₃ Al phase may be brittle, that is, a third element such as boron may be added for the purpose of suppressing grain boundary fracture. The content of the third element such as boron is preferably 1 at% or less. This provides a material that exhibits significant elongation between the yield point and the break point in a simple tensile test at ambient temperature.
The Ni ₃ Al phase may be at least partially substituted with a third element. In this case, examples of the third element include Ti, Ta, and Cu. The specific content is preferably 0 to 10 at% when Ti is the third element. Similarly, in the case of Ta, it is preferable to contain 0-5 at%. In the case of Cu, the content is preferably 0 to 10 at%. By substituting a third element such as Ti, Ta, or Cu with a part of the Ni ₃ Al phase, grain boundary fracture can be suppressed, and it is significant between the yield point and the fracture point in a simple tensile test at room temperature. A material exhibiting elongation is obtained.
The core material of this embodiment can be produced as follows, for example. That is, a Ni ₃ Al single crystal ingot is produced by unidirectional solidification, and the ingot is made into a wire through cold rolling and cold drawing. The wire is annealed and recrystallized. Although the recrystallized wire is polycrystalline, it has substantially no grain boundary impurities that cause brittleness, and therefore can be plastically deformed after yielding. In addition, when casting Ni and Al by a conventional method, an unavoidable impurity is included.

  FIG. 3 is a longitudinal sectional view showing another embodiment of the guide wire of the present invention. A guide wire 1 shown in FIG. 3 is a guide wire for a catheter that is used by being inserted into a catheter. The guide wire 1 has a wire body 40 including a first wire 20 and a second wire 30, and is a first wire disposed on the distal end side. It consists of a wire 20 and a second wire 30 joined to the proximal end side of the first wire 20, and further has a spiral coil 5 on the distal end side of the first wire 20. The total length of the guide wire 10 is not particularly limited, but is preferably about 200 to 5000 mm. Further, the outer diameter of the wire body 40 (the outer diameter of the portion where the outer diameter is constant) is not particularly limited, but is usually preferably about 0.2 to 1.2 mm.

The 1st wire 20 is a wire which has elasticity, The length is not specifically limited, However, It is preferable that it is about 20-1000 mm.
In the present embodiment, the first wire 20 has a portion having a constant outer diameter and a portion (outer diameter gradually decreasing portion) in which the outer diameter is gradually reduced toward the distal end direction. The latter may be one place or two places or more. In the illustrated embodiment, the outer diameter gradually decreasing portions 15 and 16 are provided.
By having such outer diameter gradually decreasing portions 15, 16, the rigidity (bending rigidity, torsional rigidity) of the first wire 20 can be gradually decreased toward the distal end direction. Good flexibility can be obtained at the distal end portion, the followability to blood vessels and safety can be improved, and bending and the like can also be prevented.
In the illustrated configuration, the outer diameter gradually decreasing portions 15 and 16 are each formed in a part of the first wire 20 in the longitudinal direction, but the entire first wire 20 may constitute the outer diameter gradually decreasing portion. . Further, the taper angle (decrease rate of the outer diameter) of the outer diameter gradually decreasing portions 15 and 16 may be constant along the longitudinal direction of the wire, or there may be a portion that varies along the longitudinal direction. For example, a portion in which a taper angle (an outer diameter reduction rate) and a relatively small portion are alternately formed a plurality of times may be used.
Further, unlike the illustrated configuration, the proximal end of the outer diameter gradually decreasing portion 16 is located in the middle of the second wire 30, that is, the outer diameter gradually decreasing portion 16 is connected to the joining boundary portion (welding between the first wire 20 and the second wire 30 (welding). Part) 14 may be formed.
The constituent material of the 1st wire 20 is not specifically limited, For example, various metal materials, such as stainless steel, can be used, However, Among them, the alloy (a superelastic alloy is included) which shows pseudoelasticity especially. preferable. More preferably, it is a superelastic alloy. Since the superelastic alloy is relatively flexible, has a resilience, and is difficult to bend, the guide wire 1 is sufficiently formed in the tip side portion by configuring the first wire 20 with the superelastic alloy. Flexibility and bendability can be obtained, the followability to a blood vessel that is curved and bent in a complicated manner is improved, and more excellent operability is obtained, and even if the first wire 20 repeats bending and bending deformation, Since the bend crease is not attached due to the resilience provided in the first wire 20, it is possible to prevent the operability from being lowered due to the bend crease attached to the first wire 20 during use of the guide wire 1.
Among the alloys exhibiting pseudoelasticity, a Ni-Ti alloy is particularly preferable.
The distal end of the second wire 30 is connected to the proximal end of the first wire 20 by welding. The first wire 20 and the second wire 30 may be joined by a cylindrical member. In other words, the proximal end of the first wire 20 and the distal end of the second wire 30 may be arranged and fixed in the cylindrical member.

The second wire 30 is a wire made of the following material, and its length is not particularly limited, but is preferably about 20 to 4800 mm.
The second wire 30 is made of a material containing a Ni ₃ Al intermetallic compound. Preferably, the Ni ₃ Al phase represented by the binary equilibrium diagram as shown in FIG. 2 is a material containing 25.0 to 26.5 at% Al with Ni as the main component at 400 ° C. or lower. Such a material has a wide elastic range and a high yield stress, and can be cold formed. Therefore, the second wire 30 can be reduced in diameter while sufficiently preventing the occurrence of buckling, and can have sufficient rigidity to be inserted into a predetermined portion.

Moreover, as a specific combination of the first wire 20 and the second wire 30, the first wire 20 is made of a Ni—Ti alloy, and the second wire 30 is made of a material containing a Ni ₃ Al intermetallic compound. It is composed of. By welding the first wire 20 and the second wire 30 in this combination, the joint strength of the joint boundary portion 14 between them is further increased. This is because a common metal element (for example, Ni) is contained in each constituent material of the first wire 20 and the second wire 30.

  The outer diameter of the second wire 30 is generally constant, but the outer diameter gradually decreases in the vicinity of the distal end of the second wire 30 (near the proximal end side of the joining boundary portion 14). 18. Due to the existence of the outer diameter gradually decreasing portion 18, the physical characteristics from the second wire 30 to the first wire 20, particularly elasticity, change smoothly, and excellent pushability and torque transmission performance before and after the joining boundary portion 14 are exhibited. In addition, kink resistance is also improved.

The coil 5 is a member formed by winding a wire (thin wire) in a spiral shape, and is installed so as to cover a portion on the distal end side of the first wire 20. In the configuration shown in the drawing, the portion on the distal end side of the first wire 20 is inserted through a substantially central portion inside the coil 5. Further, the tip side portion of the first wire 20 is inserted in a non-contact manner with the inner surface of the coil 5. The joining boundary portion 14 is located closer to the proximal end than the proximal end of the coil 5.
In the configuration shown in the figure, the coil 5 has a slight gap between the spirally wound wires in a state where no external force is applied, but unlike the illustration, the coil 5 is a spiral in a state where no external force is applied. Wires wound in a shape may be densely arranged without a gap.

The coil 5 is preferably made of a metal material. Examples of the metal material constituting the coil 5 include stainless steel, superelastic alloy, cobalt-based alloy, noble metals such as gold, platinum, tungsten, and alloys containing these (for example, platinum-iridium alloy). In particular, when the guide wire 1 is made of an X-ray opaque material such as a noble metal, X-ray contrast can be obtained in the guide wire 1, and the guide wire 1 can be inserted into the living body while confirming the position of the tip under X-ray fluoroscopy. It is possible and preferable. Moreover, you may comprise at least one part of the coil 5 with the material mentioned above as the core material 3 or the 2nd wire 30. FIG. The coil 5 may be composed of different materials on the distal end side and the proximal end side. For example, the distal end side may be constituted by a coil made of an X-ray opaque material, and the proximal end side may be constituted by a coil made of a material that relatively transmits X-rays (such as stainless steel). The total length of the coil 5 is not particularly limited, but is preferably about 5 to 500 mm.
The proximal end portion and the distal end portion of the coil 5 are fixed to the first wire 20 by fixing materials 11 and 13, respectively. Further, an intermediate portion (position near the tip) of the coil 5 is fixed to the first wire 20 by the fixing material 12. The fixing materials 11, 12 and 13 are made of solder (brazing material). The fixing materials 11, 12 and 13 are not limited to solder, and may be adhesives. Moreover, the fixing method of the coil 5 is not limited to a fixing material, and for example, welding may be used. In order to prevent damage to the inner wall of the blood vessel, the distal end surface of the fixing material 12 is preferably rounded.
In the present embodiment, since such a coil 5 is installed, the first wire 20 is covered with the coil 5 and has a small contact area, so that the sliding resistance can be reduced. The operability of 1 is further improved.
In the present embodiment, the coil 5 has a circular cross section of the wire, but the present invention is not limited to this, and the cross section of the wire is, for example, an ellipse or a quadrangle (particularly a rectangle). May be.
Moreover, although this embodiment is an example which used the material mentioned above for the 2nd wire 30, the 2nd wire 30 is comprised with material with a higher elastic modulus than the 1st wire 20, such as stainless steel and a cobalt base alloy. An embodiment in which at least a part of the coil 5 is made of the above-described material is also possible. Even if the coil wire is thinned due to the wide elastic range and high yield point of the above material, an extremely flexible coil can be provided, and the guide wire can be reduced in diameter.

It is preferable that the 1st wire 20 and the 2nd wire 30 which comprise the guide wire main body 40 are connected and fixed by welding. Accordingly, a high bonding strength can be obtained at the bonding boundary portion (welded portion) 14 between the first wire 20 and the second wire 30 by a simple method. The pushing force is reliably transmitted to the first wire 20.
As shown in FIG. 3, the joining boundary portion 14 has a layer shape (not only a visual layer shape but also a conceptual layer shape, including, for example, a case where a change in the content of the component is significant). The thickness of this layer is preferably about 0.001 to 100 μm, more preferably about 0.1 to 15 μm, and more preferably about 0.3 to 2 μm. The thickness of this layer may be partially thick, but is preferably substantially the same. By forming the joining boundary portion 14 in a layer shape having such a thickness, higher joining strength can be obtained. In FIG. 3, for easy understanding, the interface between the layered joining boundary portion 14 and the material of the first wire 20 and the material of the second wire 30 is clearly shown. None of these may have a visually distinct boundary.
The joint boundary portion 14 joined by welding has, in its layer, a component (metal element) in the metal material constituting the first wire 20 and a component (metal element) in the metal material constituting the second wire 30. Are mixed. In other words, the composition of the first wire 20, the joining boundary portion 14, the second wire 30, and the material constituting the first wire 20, the bonding boundary portion 14, and the second wire 30 change gradually (continuously).
For example, when the first wire 20 is made of a Ni—Ti alloy and the second wire 30 is made of the above-described material, the second wire 30 is directed from the second wire 30 side toward the first wire 20 side in the bonding boundary portion 14. The Al component tends to decrease, and the Ti component tends to decrease from the first wire 20 side toward the second wire 30 side.
Note that the content of the component (metal element) may change abruptly in the vicinity of the interface between the layered joining boundary portion 14 and the material of the first wire 20 and the material of the second wire 30.
The method for welding the first wire 20 and the second wire 30 is not particularly limited, and examples thereof include friction welding, spot welding using a laser, and butt resistance welding such as butt seam welding. Butt resistance welding is particularly preferred because high joint strength is obtained.
Such a joining boundary portion 14 has a curved surface shape. In particular, it has a curved convex shape (dish shape) that is convex toward the proximal direction of the wire body 40. Further, the curved surface of the joining boundary portion 14 has a shape that is substantially symmetric with respect to the central axis of the wire body 40. That is, the curved surface of the joining boundary portion 14 has a rotating body shape centered on the central axis of the wire body 40. As a rotating body shape of the joining boundary part 14, other than a dish shape, for example, a spherical shape, a paraboloid shape, or a shape similar to these shapes can be cited.
The following effects are acquired because the joining boundary part 14 is such a shape. That is, since the joining boundary portion 14 has a curved surface shape, the joining area becomes larger than that of the flat surface, and the effect of dispersing stress with respect to bending is produced, so that high joining strength can be obtained. Further, since the curved surface of the joining boundary portion 14 is symmetric with respect to the central axis of the wire main body 40, torque is evenly distributed from the second wire 30 to the first wire 20 when the wire main body 40 is twisted. Can be transmitted (without bias). This contributes to improved operability.

The outer diameter of the bonding boundary 14 of the wire body 40 is larger than the outer diameter of the proximal end side and the distal end side of the bonding boundary 14. That is, the predetermined region including the bonding boundary portion 14 of the wire body 40 has the protruding portion 17 that slightly protrudes (raises) in the outer peripheral direction. With such a configuration, the bonding area of the bonding boundary portion 14 can be increased, so that the bonding strength is improved, and the torsional torque and the pushing force from the second wire 30 are more reliably applied to the first wire 20. Can communicate.
Although the height of the protrusion part 17 is not specifically limited, It is preferable that it is about 1 micrometer-0.4 mm, and it is more preferable that it is about 5-50 micrometers. If the height of the projecting portion 17 is less than the lower limit value, the effect of providing the projecting portion 17 may not be sufficiently exhibited depending on the constituent materials of the first wire 20 and the second wire 30. On the other hand, when the height of the protruding portion 17 exceeds the upper limit value, the inner diameter of the lumen to be inserted into the balloon catheter is determined, so that the outer side of the second wire 30 on the proximal end side is compared with the height of the protruding portion 17. In some cases, the diameter of the second wire 30 must be reduced, and it may be difficult to fully exhibit the physical properties of the second wire 30.

As shown in FIG. 3, the wire main body 40 has a coating layer 7 that covers all or part of the outer peripheral surface (outer surface) thereof. The covering layer 7 can be formed for various purposes. As an example, the coating layer 7 reduces the friction (sliding resistance) of the guide wire 1 and improves the slidability, thereby improving the operability of the guide wire 1. May improve.
The covering layer 7 is preferably provided so as to cover at least the outer periphery of the bonding boundary portion 14. As described above, since there is a change (step) in the outer diameter of the wire body 40 in the vicinity of the bonding boundary portion 14, the outer diameter change is canceled or alleviated by covering with the coating layer 7, and the vicinity of the bonding boundary portion 14. The outer diameter of the guide wire 1 can be made substantially uniform. As a result, the operability of moving the guide wire 1 in the longitudinal direction can be improved.
For the purpose as described above, the coating layer 7 is preferably made of a material capable of reducing friction. Thereby, the frictional resistance (sliding resistance) with the inner wall of the catheter used together with the guide wire 1 is reduced, the slidability is improved, and the operability of the guide wire 1 in the catheter becomes better. Further, since the sliding resistance of the guide wire 1 is lowered, when the guide wire 1 is moved and / or rotated in the catheter, the guide wire 1 is kinked (bent) or twisted, particularly in the vicinity of the joint boundary 14. And twist can be more reliably prevented.
Examples of materials that can reduce such friction include polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polyesters (PET, PBT, etc.), polyamides, polyimides, polyurethanes, polystyrenes, polycarbonates, silicone resins, fluorine resins ( PTFE, ETFE, etc.) or a composite material thereof.
In particular, when a fluorine-based resin (or a composite material containing the same) is used, the frictional resistance (sliding resistance) between the guide wire 1 and the inner wall of the catheter is more effectively reduced, and slidability is achieved. And the operability of the guide wire 1 in the catheter becomes better. In addition, this makes it possible to more reliably prevent kinking (bending) and twisting of the guide wire 1, particularly kinking and twisting in the vicinity of the welded portion, when the guide wire 1 is moved and / or rotated in the catheter.
When a fluororesin (or a composite material containing the same) is used, the wire body 40 is usually coated with the resin material heated by a method such as baking or spraying. Thereby, the adhesiveness between the wire body 40 and the coating layer 7 is particularly excellent.
Further, if the coating layer 7 is made of a silicone resin (or a composite material containing the same), the wire body can be formed without heating when the coating layer 7 is formed (coating the wire body 40). It is possible to form the coating layer 7 which is firmly and firmly adhered to the 40. That is, when the coating layer 7 is made of a silicone resin (or a composite material containing the same), a reaction-curing material or the like can be used, so the coating layer 7 is formed at room temperature. be able to. Thus, by forming the coating layer 7 at room temperature, the coating can be easily performed, and the guide wire is maintained in a state in which the bonding strength between the first wire 20 and the second wire 30 in the welded portion 14 is sufficiently maintained. Can be operated.

Moreover, a hydrophilic material is mentioned as another preferable example of the material which can reduce friction. Examples of the hydrophilic material include cellulose-based polymer materials, polyethylene oxide-based polymer materials, and maleic anhydride-based polymer materials (for example, maleic anhydride copolymers such as methyl vinyl ether-maleic anhydride copolymer). ), Acrylamide polymer materials (for example, polyacrylamide, block copolymer of polyglycidyl methacrylate-dimethylacrylamide (PGMA-DMAA)), water-soluble nylon, polyvinyl alcohol, polyvinylpyrrolidone and the like.
The thickness of the coating layer 7 is not particularly limited, and is appropriately determined in consideration of the purpose of forming the coating layer 7, the constituent material, the formation method, and the like. And is more preferably about 2 to 15 μm. If the thickness of the coating layer 7 is too thin, the purpose of forming the coating layer 7 may not be sufficiently exhibited, the peeling of the coating layer 7 may occur, and the thickness of the coating layer 7 is too thick. Then, the physical characteristics of the wire body 40 may be affected, and the coating layer 7 may be peeled off.
Although the guide wire has been described in detail above, the core material described above can be applied to other medical devices. For example, a shaft of a wire-like insertion instrument such as a thrombus capturing instrument can be made of the above material. There is also an aspect in which the tubular shaft of the catheter is made of the above material. Since the elastic deformability is maintained even if the catheter shaft is thin and the tube thickness is reduced, it is excellent in pushability and can be inserted into the periphery of the blood vessel. Further, the lumen can be secured by reducing the thickness. Further, there is an aspect in which the coiled material is made of the above material and provided at least at the distal end portion of the catheter. Since a flexible coil can be provided, the thickness of the catheter can be reduced, and further, kink resistance can be improved while maintaining flexibility. Further, a reinforcing blade (for example, mesh shape) in which at least a part is embedded in at least a part of the inner wall of the catheter can be formed of the above material. Even if the blade wire is thin, it is flexible, so that the thickness of the catheter can be reduced, and the kink resistance and pressure resistance can be improved while maintaining torque transmission.

Next, a stent which is an embodiment of the implantable therapeutic device of the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.
FIG. 4 is a side view showing a stent which is an embodiment of the implantable therapeutic device of the present invention.
Each component constituting the stent 100 will be described in more detail below. The stent 100 is a cylindrical body that is open at both ends and extends in the longitudinal direction between the both ends. The side surface of the cylindrical body has a large number of notches 124 that communicate with the outer side surface and the inner side surface, and the notch portion 124 is deformed to have a structure that can expand and contract in the radial direction of the cylindrical body. It is placed in a blood vessel, such as a blood vessel or bile duct, and maintains its shape.

  In the embodiment shown in FIG. 4, the stent 100 is composed of a band-shaped member 120, and has a substantially rhomboid element 121 having a notch 124 inside as a basic unit. A plurality of substantially diamond-shaped elements 121 are arranged in an annular unit 122 by arranging and combining substantially diamond-shaped elements continuously in the minor axis direction. The annular unit 122 is connected to an adjacent annular unit via a linear elastic member 123. Thus, the plurality of annular units 122 are continuously arranged in the axial direction in a partially coupled state. With such a configuration, the stent 100 has a cylindrical body that is open at both end portions and extends in the longitudinal direction between the both end portions. The stent 100 has a substantially rhombic cutout portion 124, and the cutout portion 124 is deformed to expand and contract in the radial direction of the cylindrical body.

The material of the stent 100 is made of a material containing a Ni ₃ Al intermetallic compound. Such a material is a Ni ₃ Al phase shown in a binary equilibrium diagram as shown in FIG. 2 and contains 25.0 to 26.5 at% of aluminum (Al) at 400 ° C. or lower. Further, the material of the stent 100 is a Ni ₃ Al phase + Ni phase represented by a binary equilibrium diagram as shown in FIG. % May be included. This material preferably has a Ni ₃ Al phase as a matrix and a Ni phase as an island. The Ni ₃ Al phase is a matrix and the Ni phase is an island material, so it has a high yield point, but has a relatively wide elastic range. Since the above material has a high yield point, it has excellent strength, and even a thinned stent can expand a lesion and maintain its expansion. Furthermore, since the above materials are also supple, they are excellent in reachability (delivery) to the lesioned part of the stent, and follow the body movement and pulsation after placement, so that the placed site is overstimulated. Demonstrate the excellent effect of not giving.

What is necessary is just to select the magnitude | size of a stent main body suitably according to an application location. For example, when used for the coronary artery of the heart, the outer diameter before expansion is usually 1.0 to 3.0 mm, and the length is preferably 5 to 50 mm. As shown in FIG. 4, when the stent is configured by a band-shaped member, the length in the width direction of the band-shaped member configured to have the plurality of notches 124 is preferably 0.005 to 0.5 mm. More preferably, it is 0.01-0.2 mm.
In the present invention, the stent 100 is not limited to the illustrated embodiment, and both end portions are cylindrical bodies that open in the longitudinal direction between the both end portions. And a large number of notches that communicate with the inner surface, and by deforming the notches, widely includes a structure that can be expanded and contracted in the radial direction of the cylindrical body.
The cross-sectional shape of the band-shaped member constituting the stent 100 is not limited to a rectangle, and may be other shapes such as a circle, an ellipse, and a polygon other than a rectangle.

The expansion means of the stent 100 after indwelling is not particularly limited, and is a self-expanding type, that is, a type that expands in the radial direction with its own restoring force by removing the force holding the stent body thinly and smallly folded. It may be. However, the stent of the present invention is preferably of a balloon expandable type, that is, a type in which the balloon is expanded from the inside of the stent body and the stent is expanded in the radial direction by the external force.
The manufacturing method of a stent is not specifically limited, According to the structure and material of a stent, what is necessary is just to select suitably from the manufacturing method used normally.
The outer surface of the linear member 120 constituting the stent 100 that comes into contact with the living tissue may be coated with a polymer that slowly releases a drug that inhibits re-occlusion of the blood vessel.
Although the implantable therapeutic device of the present invention has been described by taking a stent as an example, it is not limited to a stent, and includes all devices that are implanted in a vessel such as a blood vessel or a bile duct, such as a stent graft used for treatment of an aortic aneurysm.

It is a longitudinal cross-sectional view which shows one Embodiment of the guide wire of this invention. It is a binary equilibrium diagram of nickel (Ni) and aluminum (Al). It is a longitudinal cross-sectional view which shows other embodiment of the guide wire of this invention. It is a side view which shows the stent which is one Embodiment of the implantable therapeutic device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 10 Guide wire 3 Core material 5 Coil 7 Coating layer 14 Joining boundary part (welding part)
20 First wire 30 Second wire 40 Wire body 100 Stent 124 Notch

Claims (6)

A guide wire comprising a first wire disposed on a distal end side and a second wire joined to a proximal end side of the first wire, wherein the first wire is made of a Ni-Ti alloy, A guide wire characterized in that the second wire is made of a material containing a Ni3Al intermetallic compound. 2. The guide wire according to claim 1, wherein the material is a Ni 3 Al phase represented by a binary equilibrium diagram and includes 25.0 to 26.5 at% Al with Ni as a main component at 400 ° C. or lower. 2. The guide wire according to claim 1, wherein the material is a Ni 3 Al phase + Ni phase represented by a binary equilibrium diagram, and contains 7.2 to 25.0 at% of Al containing Ni as a main component at 400 ° C. or lower. 2. The guide wire according to claim 1, wherein the material is a Ni 3 Al phase + Ni 5 Al 3 phase represented by a binary equilibrium diagram and includes 26.5 to 32.0 at% of Al containing Ni as a main component at 400 ° C. or lower. The guide wire according to claim 1, wherein the material is made of a material composed of a Ni3Al phase having an L12 type regular structure. The guide wire according to claim 5, wherein a third element is added to the Ni3Al phase for the purpose of suppressing grain boundary fracture.

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