JP5735159B1 - Medical guidewire - Google Patents

Abstract

The present invention provides a medical guide wire that has improved rotation transmission performance to the distal end side and perforation performance of a lesioned portion as the core wire is thinned into a coil body. A core wire front end portion 2B in a coil body 3 has an articulated frustoconical body in which at least two or more frustoconical bodies are joined in the longitudinal direction, and a cross-sectional secondary moment from the rear end side to the front end side. By satisfying a certain relational expression, when the core wire 2 on the proximal side is rotated, the rotational angle on the proximal side is decreased and the torsional moment toward the distal end is increased to improve the perforation performance of the obstructed lesion. Can do. [Selection] Figure 1

Description

  The present invention relates to a medical guide wire used for treating a vascular lesion.

  Conventionally, when treating vascular lesions such as vascular stenosis and occlusions, a medical guide wire (hereinafter referred to as a guide wire) provided with a coil at the tip of a thin core wire is used to bring the tip to the lesion. A diameter expansion treatment is performed for a vascular lesion such as a stenosis part of a blood vessel and a completely occluded part.

  In such a case, in order to penetrate the guide wire into the vascular lesion, high rotation transmission performance, perforation performance, and repeated fatigue resistance from the proximal side (rear end side) to the distal end side are required.

  Patent Document 1 describes a guide wire related to characteristics such as bending rigidity of a core wire on the hand side (rear end side) with respect to a coil on the front end side.

  Patent Document 2 describes a guide wire in which a densely wound portion is provided at the center of a coil on the distal end side, and a loosely wound portion is provided at both ends of the densely wound portion.

Japanese Patent No. 4623906 JP 2010-222 A

  In the guide wire described in Patent Document 1, the core wire is made of stainless steel or a nickel-titanium superelastic metal, and the core wire closer to the proximal side than the coil on the front end side changes in a bending rigidity linearly in the longitudinal direction, and is abrupt. It is a technical content that eliminates resistance and improves the operability of the surgeon.

  The guide wire described in Patent Document 2 is a technique for preventing the bias of the resin coating when the resin coating is applied to the outer periphery of the coil by providing a gap at both ends of the coil and providing an initial tension at the densely wound portion at the center. Content.

  Both Patent Documents 1 and 2 specify a thin core wire shape and mechanical strength characteristics in the coil, and arrange a coil having an initial tension on the outside of the thin core wire, and use these together. Increases the torsional force (torsional moment) to the tip side while reducing the rotation angle on the hand side, improving the high rotational transmission performance, torsional rigidity, and buckling strength to the tip side, thereby blocking the lesion There is no description about the technical contents that improve the perforation performance in the section. These performances are important technical issues for passing a guide wire through a vascular lesion.

  This invention is made | formed in view of the said subject, and it aims at providing the guide wire which improves the permeability | transmittance in a vascular lesion part drastically.

In order to achieve the above object, a guide wire according to the present invention includes a core wire tip portion having a portion that gradually changes in diameter from the rear end side to the tip end side, and is inserted into the coil body, so that the rear end of the coil body and the tip end of the core wire are inserted. The rear end of the coil portion is joined at the rear end joining portion, and the tip end of the coil body and the tip end of the core wire tip end portion are joined at the tip-shaped tip joining portion .
Coil body, the distal end side of winding a wire of radio-opaque, by winding in the form of the rear end side is twisted with wire radiolucent, Ru provided close coiled portion which initial tension acts.
Core distal portion of the coil body has a tensile strength using a wire of 3500 N / mm ² of austenitic stainless steel from 2200N / mm ^2, the rear end is in a truncated cone, at least two or more from the rear end to the front end side truncated cones to have an articulated truncated cones which continuously connected longitudinally, the longitudinal length of one truncated cone, truncated cones of distally from truncated cones of the rear end of the gradual change decreased towards, the second moment of articulation truncated cone, gradual change decreased toward the rear end or al the tip side and the maximum outer diameter and the minimum outer diameter of the connecting truncated cones When one truncated cone connected by a straight line is a virtual single truncated cone (hereinafter referred to as a virtual single truncated cone), the cross-sectional secondary of the connected truncated cone at an arbitrary position in the longitudinal direction The moment is the secondary cross-section of the virtual single truncated cone at the same position as the arbitrary position in the longitudinal direction. To be larger than Mento.
The close coiled portion of the coil body has a tensile strength using a wire of 3500 N / mm ² of austenitic stainless steel from 2200N / mm ^2, to lower the spring index of the front end side than the rear end side, articulated截The initial tension of the tightly wound portion of the coil body is reduced from the rear end side to the front end as the sectional moment of inertia of the articulated truncated cone gradually decreases from the rear end to the front end side. It is characterized by gradually increasing to the side .

Further, the densely wound portion of the coil body has a mirror-like appearance of the coil wire, a spring index C of 2.5 or more and 6.8 or less from the rear end side to the front end side, and the torsional stress due to the initial tension is τ (N / mm ² ), the torsional stress τ (N / mm ² ) includes a rear end large diameter equal portion, an intermediate taper portion, and a small tip diameter equal diameter portion that satisfy a certain relational expression, and the intermediate taper portion is the maximum. The initial tension of the densely wound portion of the intermediate taper portion may be gradually increased from the rear end side to the front end side .

Further, when the spring index C at the rear end of the intermediate taper portion is 4.50 and the spring index C at the tip end small diameter portion is 3.33, the initial tension of the closely wound portion of the intermediate taper portion is 5 .13 × 10 ⁻² N to 9.36 × 10 ⁻² N may be gradually increased from the rear end side to the front end side .

The guidewire of the present invention, the transmural interpolating core distal portion to the coil body, a tensile strength using a wire of 3500 N / mm ² of austenitic stainless steel from 2200N / mm ^2, the rear end is in a truncated cone, has a connecting truncated cone at least two or more truncated cones distally continuously connected longitudinally from the rear end, the longitudinal length of one truncated cone, the rear end truncated and cone tip side of gradual change decreases toward the truncated cones from the second moment of articulation truncated cone, gradual change decreased toward the rear end or al the tip side and connecting frustoconical The cross-sectional secondary moment of the body is larger than the cross-sectional secondary moment of the virtual single truncated cone at the same position as the longitudinal connecting truncated cone, so that the wire with high torsional stress and high transverse elastic modulus the obtained, when rotating the hand side, the proximal times Angle reduces, to improve flexural rigidity and buckling resistance column strength of the core wire distal end portion, Ru can increase the torsional moment in the tip side.

Further, the close coiled portion of the coil body, a tensile strength is wound by the action of the initial tension in the form of twisted wire rod of austenitic stainless steel 3500 N / mm ² from 2200N / mm ^2, the rear end side The spring index on the front end side is also lowered, and the coil body is disposed outside the articulated truncated cone, and the cross sectional second moment of the articulated truncated cone gradually decreases from the rear end to the front end side. The initial tension of the densely wound portion is gradually increased from the rear end side to the front end side.
The tightly wound portion of the coil body is wound in a twisted form using a high tensile strength austenitic stainless steel wire wire to obtain a high transverse elastic modulus and increase torsional stress, while at the same time high initial tension Can act.
Moreover, by lowering the spring index on the front end side than on the rear end side, it is possible to increase the torsional stress of the closely wound portion on the front end side and simultaneously increase the initial tension.
And it is arranged outside the articulated truncated cone with a lower spring index on the front end side than the rear end side, and the cross-sectional second moment of the articulated truncated cone gradually decreases from the rear end to the front end side. Thus, the initial tension of the tightly wound portion of the coil body is gradually increased from the rear end side to the front end side, and the connecting truncated cone whose sectional secondary moment is gradually decreased from the rear end to the front end side, the torsional stress and the initial the Rukoto be used together with close coiled portion of the coil body with increased tension reduces the rotation angle of the proximal side, to improve the bending rigidity and buckling resistance column strength, to increase the torsional moment distally, the distal end High rotation transmission performance to the side and perforation performance at the occluded lesion can be improved .

Furthermore, the densely wound portion of the coil body has a mirror-like appearance of the coil wire, and the torsional stress due to the initial tension is τ (N / N) when the spring index C is 2.5 to 6.8 from the rear end side to the front end side. mm ² ) having a large rear end diameter equal diameter portion, an intermediate taper portion, and a small tip diameter equal diameter portion satisfying a certain relational expression, the intermediate taper portion being disposed outside the most advanced truncated cone, The initial tension of the closely wound part of the part may be gradually increased from the rear end side to the front end side.
To the outside of the state-of-the-art truncated cone, whose diameter decreases from the rear end side to the front end side, lower the spring index on the front end side than the rear end side, and increase the torsional stress and initial tension to be strong between the coil wires By arranging the intermediate taper part of the tightly wound part that acts on the adhesion force, the rotation angle on the proximal side due to the connecting truncated cone structure at the tip of the core wire is reduced while being thin, further increasing the bending rigidity and buckling strength. improve, Ru can further increase the torsional moment in the tip side.

Furthermore, when the spring index C of the rear end diameter large equal diameter part of the rear end of the intermediate taper part is 4.5 and the spring index C of the small end diameter constant diameter part of the front end is 3.3, the initial value of the intermediate taper part is The tension may be gradually increased from 5.13 × 10 ⁻² N to 9.36 × 10 ⁻² N from the rear end to the front end.
The tip from the rear end to the outside of the cutting-edge truncated cone that reduces the moment of inertia of the cross section toward the distal end while being the tip of the core of the connecting truncated cone that increases the torsional moment toward the distal end. By placing an intermediate taper part with the highest initial tension to the side, the effect of reducing the rotation angle of the proximal side of the guide wire used especially for cardiovascular treatment and the action of increasing the torsional moment to the distal side are achieved. Can be complemented .

BRIEF DESCRIPTION OF THE DRAWINGS It is the side view which showed the whole guide wire 1 of 1st Embodiment of this invention, and partly notched. It is a side view which shows the connection truncated cone of 1st Embodiment with which two truncated cones are connected. It is a side view which shows the connection truncated cone of 2nd Embodiment to which three truncated cones are connected. It is a side view which compares and shows the difference of the cross-sectional secondary moment of the connection truncated cone of a core wire front-end | tip part, and a virtual single truncated cone. The correlation between the spring index of a coil body and torsional stress is shown. The correlation between the spring index of the coil body and the deformation occurrence rate is shown. It is a principal part side view of the front-end | tip part of the guide wire of 3rd Embodiment of this invention.

  Hereinafter, embodiments of the guide wire (medical guide wire) of the present invention will be described. Of course, the embodiments described below are merely illustrative of the present invention.

(First embodiment)
FIG. 1 shows a guide wire 1 according to a first embodiment of the present invention. The guide wire 1 has a core wire 2, a coil body 3, a fluororesin film 6, and a hydrophilic resin film 7.
The core wire 2 has a core wire rear end portion 2A and a core wire front end portion 2B, and is gradually changed in diameter from the rear end side to the front end side. The coil body 3 is inserted through the core wire tip 2B, the rear end of the coil body 3 and the rear end of the core wire tip 2B are joined by the rear end joint 5B, and the tip of the coil body 3 and the tip of the core wire tip 2B are joined. Are joined by a tip-shaped tip joint portion 5A . The fluororesin 6 is formed on the outer periphery of the thick core wire 2 on the rear end side. The hydrophilic resin film 7 is formed on the outer periphery of the coil body 3. The guide wire 1 of the present invention has a value smaller in diameter than the length, and it becomes difficult to illustrate within a predetermined range if the vertical and horizontal scale ratios are the same. It is shown by omission or omission.

  The core wire 2 has a first equal diameter portion 21, a first taper portion 22, a second equal diameter portion 23, a second taper portion 24, a third equal diameter portion 25, and a heel described later, from the rear end side toward the front end side. The outer diameter is 0 in the order of the connecting truncated cone 26 in which the head cones are connected (in the first embodiment, the first truncated cone 26A and the second truncated cone 26B are connected) and the fourth equal-diameter portion 27. 3. Gradually reduce diameter from 3556 mm (0.014 inch for cardiovascular therapy) to 0.060 mm.

Moreover, as a material of the core wire 2, a stainless steel wire, a Ni-Ti alloy wire, etc. are used, and as a manufacturing method, as shown in Unexamined-Japanese-Patent No. 2002-69586, a wire-stretching process and an annealing process are repeated and high strength is carried out. It is a stainless steel wire or a Ni—Ti alloy wire that has been heat-treated under predetermined conditions as disclosed in JP-A-2002-69555. Preferably, an austenitic stainless steel wire having a tensile strength of 2200 MPa to 3500 MPa is used.
This is because the austenitic stainless steel wire having a high transverse elastic modulus is obtained by easily improving the tensile strength by the reduced diameter drawing process, and the connecting truncated cone 26 described later is a thin core wire. This is because, by providing a high torsional stress, the rotation transmission performance to the tip side can be enhanced. Further, since the hardness is increased by improving the tensile strength, centerless grinding of the shape of the connecting truncated cone 26 of the core wire 2 is facilitated. Here, the connected truncated cone 26 refers to a structure in which a plurality of truncated cones are provided in the longitudinal direction by performing grinding or the like using one wire. Moreover, the core wire front end portion 2B and the core wire rear end portion 2A may be the core wire 2 in which different wire materials are welded and joined, for example, a combination of the materials of the core wire.

The coil 3 is an outer diameter A1 of 0.330 mm, a longitudinal length of 160 mm, a coil wire diameter d0 of 0.060 mm, and a coil formed by winding one or more wires.
A longitudinal length of the first coil body 31 having a longitudinal length of 30 mm made of platinum or a radiopaque wire of platinum and nickel on the front end side and a radiation transmitting wire of a stainless steel wire on the rear end side. Consists of a second coil body 32 of 130 mm.

  The first coil body 31 includes a sparsely wound portion 31A, and the coil pitch P0 of the sparsely wound portion 31A is less than twice the diameter of the strand 8A, and is 1.05 times 1 or more of the diameter d0 of the strand 8A. 90 times or less is preferable, and in the present embodiment, it is 1.25 times. In the present embodiment, since the diameter d0 of the wire 8A is 0.060 mm, 1.25 times the coil pitch is 0.075 mm. The sparsely wound portion 31A may be provided with a densely wound portion on the rear end side as long as at least 10 mm can be secured from the inside of the front end joint portion 5A. (In the first embodiment, the sparsely wound portion 31A over the entire length)

The first coil body 31 and the second coil body 32 are screwed with a coil wire and joined by means such as a brazing material at the intermediate joint 5C. Further, instead of screw-joining, coil wires may be joined together by means such as welding. The material of the coil wire of the second coil body 32 is preferably an austenitic stainless steel wire having a tensile strength of 2200 MPa to 3500 MPa among stainless steel wires.
The reason for this is that the tensile strength is easily improved by reduced diameter drawing, and the initial tension is increased by obtaining a high torsional stress by using a coil wire having a high transverse elastic modulus to perform a close winding. Because it can.

  2 and 3 show core tip portions 2B and 2C having different shapes, and FIG. 2 shows the core tip portion 2B of the first embodiment in which the truncated cone has two connected truncated cones 26. FIG. . FIG. 3 shows the core wire tip 2C of the second embodiment when there are three truncated cones. Except for the core end portions 2B and 2C, the other specifications are the same as those of the first embodiment, and the same components are denoted by the same reference numerals.

In FIG. 2, the core wire front end portion 2B is composed of a connecting truncated cone 26 and a fourth equal-diameter portion 27 from the rear end side to the leading end side, and the connecting truncated cone 26 has a longitudinal length L1 of 100 mm. A first truncated cone 26A having a large outer diameter D0 of 0.180 mm and a small outer diameter D2 of 0.125 mm, the outer diameter of which gradually decreases from the rear end side to the node 28A on the front end side; The length L2 in the direction is 50 mm, the large outer diameter D2 is 0.125 mm when viewed from the second truncated cone 26B, and the small outer diameter D1 is 0.060 mm from the node 28A on the rear end side to the front end side. It consists of two truncated cones of the second truncated cone 26B whose outer diameter gradually decreases.
Then, with the node 28A as a boundary, the outer diameter of the first truncated cone 26A and the outer diameter of the second truncated cone 26B are gradually reduced. The gradual decrease referred to here is not the case where the outer diameters of the first truncated cone 26A and the second truncated cone 26B decrease at a fixed rate, but the fixed rate at the node 28A. , Both in the case of a gradual decrease.

  The fourth equal diameter portion 27 has a length L0 in the longitudinal direction of 10 mm and an outer diameter D1 of 0.060 mm. The core wire tip 2B may or may not be provided with the fourth equal-diameter portion 27. If the flexibility of the most advanced portion is important, it is provided when the most advanced drilling capability is important. It is preferable not to provide. The choice depends on the symptoms of the lesion. Further, the rear end joint portion 5B, the intermediate joint portion 5C, and the hydrophilic resin film 7 are omitted.

  The longitudinal length L1 of the first truncated cone 26A is 100 mm, and the longitudinal length L2 of the second truncated cone 26B is 50 mm, which decreases from the rear end side to the distal end side (L1> L2). .

(Second Embodiment)
In FIG. 3, the core wire front end portion 2C has a length in the longitudinal direction from the rear end side to the front end side of L1 (mm), a large outer diameter of D0 (mm), and a small outer diameter of D2 (mm). A first truncated cone 26A in which the outer diameter from the rear end side to the distal end node 28B gradually decreases and a length in the longitudinal direction is L2 (mm), and the diameter as viewed from the second truncated cone 26B. A second truncated cone having a large outer diameter of D2 (mm) and a small outer diameter of D3 (mm), the outer diameter from the rear end side node portion 28B to the distal end side node portion 28C gradually decreasing. 26B, the length in the longitudinal direction is L3 (mm), the large outer diameter is D3 (mm) when viewed from the third truncated cone 26C, and the small outer diameter is D1 (mm). A third truncated cone 26C whose outer diameter gradually decreases from the node 28C toward the distal end side is composed of an articulated truncated cone 30 connecting three truncated cones.
The outer diameter of the first truncated cone 26A, the outer diameter of the second truncated cone 26B, and the outer diameter of the third truncated cone 26C are stepwise with respect to the nodes 28B and 28C. Decrease gradually. In addition, the 4th equal diameter part 27 shown in FIG. 2 is not provided.

  Similarly to the above, the longitudinal length of one truncated cone of the connected truncated cone 30 gradually decreases from the rear end side to the distal end side (L1> L2> L3). Further, the outer diameter also gradually decreases (D0> D2> D3) from the rear end side to the front end side.

Thus, the core wire tips 2B and 2C of the present invention are connected truncated cones 26 and 30 in which at least two truncated cones are connected in the longitudinal direction, and the longitudinal direction of one truncated cone Is gradually reduced from the first truncated cone 26A on the rear end side to the second truncated cone 26B on the distal end side and from the first truncated cone 26C to the distal truncated cone in the order of the third truncated cone 26C. It is characterized by doing.
This is because, together with the relational expression of the moment of inertia of the cross section described later, the rotation angle on the hand side is reduced to increase the torsional moment toward the tip side, and the high rotation transmission performance to the tip side results in narrowing. This is to improve the perforation performance at the site and the completely occluded lesion.

FIG. 4 is an explanatory diagram showing a relational expression between the cross-sectional secondary moment of the connecting truncated cone 26 of the core wire tip 2B and the cross-sectional secondary moment of the virtual single truncated cone 260 of the present invention. The solid line in the figure shows the connecting truncated cone 26 in the case of two truncated cones according to the first embodiment of the present invention, and the two-dot chain line is a virtual virtual single truncated cone for explaining the relational expression. A body 260 is shown.
The articulated truncated cone 26 has a maximum outer diameter of D0 (mm), a minimum outer diameter of D1 (mm), a total length of L (mm), and a length from the center position of the cross section of the maximum outer diameter D0 (mm). The cross-sectional second moment of the articulated truncated cone 26 at an arbitrary position X in the direction is Im (mm ⁴ ), the outer diameter is Dm (mm), and the maximum outer diameter D0 and the minimum outer diameter D1 are two-dot chain lines. When the cross sectional second moment of one virtual single truncated conical body 260 connected at is Ix (mm ⁴ ) and the outer diameter is Dx (mm), the outer diameter Dx (mm) is
Dx = D0− (D0−D1) X / L (1)
This can be expressed by the relational expression (1). The cross-sectional secondary moment Ix (mm ⁴ ) and the outer diameter Dx (mm) are
^{Ix = πDx 4/64 ··· (} 2)
The relational expression (2).
Since the sectional secondary moment Ix (mm ⁴ ) and the outer diameter Dx (mm) are expressed by the relational expressions (1) and (2), respectively, the sectional second moment at an arbitrary position X (mm) in the longitudinal direction is obtained. The next moment Ix (mm ⁴ ) is
Ix = π {D0- (D0- D1) X / L} 4/64 ··· (3)
It can be represented by the relational expression (3).
The cross-sectional secondary moment Im (mm ⁴ ) of the articulated truncated cone 26 at an arbitrary position X (mm) in the longitudinal direction is greater than the cross-sectional secondary moment Ix (mm ⁴ ) of the virtual single truncated cone 260. (Im> Ix). In this case, the secondary moment of inertia Im (mm ⁴ ) is
Im> π {(L × D0− (D0−D1) X)} ⁴ / (64 × L ⁴ ) (4)
The relational expression (4) can be expressed.

Thus, the core wire tips 2B and 2C of the present invention are connected truncated cones 26 and 30 in which at least two truncated cones are connected in the longitudinal direction, and the longitudinal direction of one truncated cone Is gradually reduced from the first truncated cone 26A on the rear end side to the second truncated cone 26B on the distal end side and the truncated cone on the distal end side of the third truncated cone 26C. In addition, the cross-sectional secondary moment Im at any position X in the longitudinal direction of the connected truncated cones 26 and 30 is larger than the cross-sectional secondary moment Ix of the virtual single truncated cone 260 at the same position (Im> Ix And the relational expression (4) is satisfied.
The reason for this is that when the core wire on the hand side is rotated, the rotation angle on the hand side is decreased, the bending rigidity and buckling resistance of the core wire tip are improved, and the torsional moment toward the tip side is increased, thereby causing lesions. This is because it is possible to obtain the core wire tip portions 2B and 2C that further improve the perforation performance and fatigue resistance characteristics at the portion.

More specifically, the nodes 28A, 28B, and 28C that cannot be formed by the virtual single truncated cone 260 are formed by gradually decreasing the longitudinal length of one truncated cone from the rear end side to the distal end side. Can be formed on the tip side. The sectional secondary moments of the nodes 28A, 28B, and 28C are larger than the sectional secondary moment of the virtual single truncated cone 260 at the same position. Thus, to reach the core wire distal end to the lesion, when rotating the core wire of the proximal side in order to be drilled into the lesion portion, it reduces the screw Re corners of the core wire, reducing the rotation angle of the resulting proximal be able to. This is because the torsion angle is proportional to the torsional stress, and the torsional stress is inversely proportional to the cross-sectional second moment.
Further, when the hand side is pushed and pulled, the bending rigidity and the buckling resistance of the core wire tip portions 2B and 2C can be improved. This is because the bending stiffness can be expressed by the product of the longitudinal elastic modulus and the cross-sectional second moment.
Further, the compressive stress is inversely proportional to the area of the cross section, and if the area of the cross section is large, the cross-sectional secondary moment increases and the compressive stress decreases.
Furthermore, the torsional moment of the core wire tip portions 2B and 2C can be increased. This is because the torsional moment can be expressed by the product of the torsional stress and the cross-sectional secondary moment, and is proportional to the cross-sectional secondary moment.

  Next, the correlation between the torsional stress τ and the spring index C will be described with reference to FIG. As shown in FIG. 5, N1, N2, and N3 are approximate expressions when the spring index C is 2.5 or more and 6.8 or less, and the inside of this range is a solid line and the outside of the range is a dotted line.

FIG. 5 is a graph showing the correlation between the torsional stress τ (N / mm ² ) and the spring index C, where the horizontal axis is the spring index C and the vertical axis is the torsional stress τ (N / mm ² ). Such a correlation between the torsional stress τ (N / mm ² ) and the spring index C is derived from a result of a test performed in advance.
When the torsional stress of the tightly wound portion 32B of the second coil body 32 and the tightly wound portion 42B of the second coil body 42 described later is τ (N / mm ² ) and the spring index is C, the spring index C is 2. 5 to 6.8 and the torsional stress τ (N / mm ² ) of the closely wound portions 32B and 42B is
−11.2C + 111.7 ≦ τ ≦ −38.7C + 370.6 (5)
It is preferable to satisfy the relational expression (5). (Range of reference symbols N1 and N3)
The reason for this is that if the value falls below the lower limit value, the contact force (compression force) due to the initial tension acting between the coil wires of the densely wound portion 32B decreases, and the torsional moment of the connecting truncated cone 26 of the core wire tip 2B increases. It becomes impossible to supplement the effect of improving the rotation transmission performance to the tip side by the action.
On the other hand, if the upper limit is exceeded, the close contact force due to the initial tension acting between the coil wires of the densely wound portion 32B becomes excessive, and the rigidity of the boundary portion between the densely wound portion 32B and the loosely wound portion 31A of the first coil body 31 is increased. The difference becomes prominent, the radius of curvature at the boundary does not gradually decrease toward the tip side, and a sharp bend is likely to occur, making it impossible to supplement the effect of improving the rotation transmission performance to the tip side. Because.

More preferably, the spring index C is 2.5 or more and 6.8 or less, and the torsional stress τ (N / mm ² ) of the closely wound portion is
−21.8C + 198.1 ≦ τ ≦ −38.7C + 370.6 (6)
It is preferable to satisfy the relational expression (6). (Range of reference symbols N1 and N2)
The initial tension F is: F = πd ³ τ / (8D) (7) where the coil wire diameter is d, the torsional stress is τ, and the coil average diameter is D.
In FIG. 5, the relational expressions (5) and (6) are derived from many test results.

Then, a high initial tension is applied to the outside of the articulated truncated cones 26 and 30 that improve the performance of transmitting the rotation to the tip side, and a first range of torsional stress that satisfies the relational expressions (5) and (6) is satisfied. A two-coil body 32 is arranged.
The reason for this is that a strong compressive force (adhesion force) is applied between the coil wires to the tightly wound portion 32B having an increased initial tension, and the second coil body 32 having the increased adhesion force is connected to the connecting truncated cones 26, 30. By arranging the outer side of the wire, the phenomenon of lowering the rotational transmission performance to the tip side is suppressed, and the structure of the core wire tip portions 2B and 2C of the connecting truncated cones 26 and 30 and the compression force between the coil wires are increased. This is because the combined use with the second coil body 32 can dramatically improve the rotation transmission performance from the rear end side to the front end side.

This initial tension can be obtained by providing a negative coil pitch and performing winding forming during coil forming. The reason for this is that the coil wire cannot be freely rotated at the time of the winding forming and is wound in a twisted form.
Therefore, the initial tension can be increased or decreased by increasing or decreasing the negative amount of the negative coil pitch. Thereby, from the correlation with the loosely wound portion 31A of the first coil body 31, the torsional stress due to the initial tension of the densely wound portion 32B of the second coil body 32 is set to be high or set to be low. Can do.

When the outer diameter A1 of the second coil body 32 is 0.330 mm, the torsional stress τ1 of the densely wound portion 32B is about 163.4 N / mm ² . Since the spring index C1 is 4.50, when the torsional stress τ1 of this value is τ and the spring index C1 is C and is substituted into the relational expression (6), the range of the upper and lower limit values of the torsional stress τ is about 100 N / mm ² or more 196 N / mm ^2, and the torsional stress τ1 is within this range. Similarly, the relational expression (5) is also satisfied.
When the torsional stress τ1 is 163.4 N / mm ² and the initial tension of the densely wound portion 32B is F1, the initial tension F1 is about 5.13 × 10 ⁻² N from the relational expression (7). is there. This is because when the initial tension is applied to the densely wound portion 32B of the second coil body 32, the initial tension F1 acts as a resistance force to the initial tension until the adjacent coil wires are separated (until the gap is opened), By the action of this initial tension, in which a compression force is applied in advance between the coil wires in advance to increase the adhesion force, it is possible to supplement the improvement of the rotation transmission performance to the tip side when the hand side is rotated.

    Next, when the spring index C of the second coil body 32 is changed, the spring index C and the deformation rate (%) will be described.

FIG. 6 is a graph showing the correlation between the deformation rate (%) and the spring index C, where the horizontal axis is the spring index C and the vertical axis is the deformation rate (%). Such a correlation between the deformation occurrence rate (%) and the spring index C is derived from a result of a test performed in advance using an evaluation apparatus.
As shown in FIG. 6, the deformation rate (%) increases rapidly when the spring index C exceeds 6.8, and when the spring index C falls below 2.5, the coil body 3 is formed by spirally winding. When this occurs, scales, cracks, etc. are likely to occur on the surface of the wire of the coil body 3. Therefore, the spring index C of the coil body 3 is 2.5 or more and 6.8 or less in consideration of the deformation occurrence rate (%). Deformation rate (%) here refers to the plastic deformation performance of the coil part obtained by repeatedly inserting each test product with a different spring index into the evaluation device 20 times and evaluating the insertion characteristics and rotation transmission performance. This is the failure rate (%). The evaluation device is composed of an inlet portion having an inner diameter of 2 mm and a bent meandering portion provided with six 180 ° bent portions having a radius of 5 mm, and is formed by a resin tube made of fluorine resin or the like.

(Third embodiment)
In the guide wire 1 of the first embodiment, the coil body 3 is formed with the same outer diameter from the rear end side to the front end side as shown in FIG. 1, but the guide wire 10 of the third embodiment is as shown in FIG. Further, the outer diameter of the coil body 4 is gradually changed from the rear end side toward the front end side. Other configurations are the same as those of the first embodiment, and the same components are denoted by the same reference numerals and redundant description is omitted.

The coil body 4 is a second coil body 42 made of a stainless steel radiation transmissive wire on the rear end side, and a first coil body 41 made of platinum or a platinum and nickel radiation opaque wire on the front end side.
The second coil body 42 is a densely wound portion 42B, the first coil body 41 is a loosely wound portion 41A, and the loosely wound portion 41A is within a range of at least 10 mm from the inside of the tip-shaped tip joint portion 5A to the proximal side. Provided. It should be noted that the coil pitch Po of the sparsely wound portion 41A of the first coil body 41, the line spacing to of the wire 8A, the diameter do of the wires 8A and 8B, the second coil body 42 of the coil body 4 and the first coil body 41 The material and the point of forming at least one strand 8A and 8B in a spiral shape into a cylinder are the same as in the first embodiment. Moreover, the 1st coil body 41 and the 2nd coil body 42 are joined by the intermediate junction part 5C similarly to 1st Embodiment.

  The coil body 4 gradually decreases from the rear end side to the front end side in the order of the rear end diameter large equal diameter portion 411, the intermediate taper portion 412, and the front end diameter small equal diameter portion 413. The rear end diameter large equal diameter portion 411 has an outer diameter B1 of 0.330 mm and a coil average diameter Bo1 of 0.270 mm. The intermediate taper portion 412 has an outer diameter that gradually changes from 0.330 mm to 0.260 mm. The tip diameter small equal diameter portion 413 has an outer diameter B2 of 0.260 mm and a coil average diameter Bo2 of 0.200 mm.

  The total length of the coil body 4 is 160 mm, the rear end diameter large equal diameter portion 411 is the closely wound portion 42B, the length in the longitudinal direction is 100 mm, the intermediate taper portion 412 is the closely wound portion 42B, and the length in the longitudinal direction is The constant diameter portion 413 having a small tip diameter of 30 mm is a loosely wound portion 41A having a length in the longitudinal direction of 30 mm. In addition, the tip diameter small equal diameter part 413 may secure the length of the sparsely wound part 41A at least 10 mm or more from the inside of the tip joint part 5A, and may provide a tightly wound part on the rear end side. The length in the longitudinal direction is preferably 1/3 or more of the total length L0 of the small-diameter portion 413 with a small tip diameter.

When the maximum outer diameter of the guide wire used for the cardiovascular treatment is 0.3556 mm (0.014 inch), the outer diameter B1 of the rear end diameter larger equal diameter portion 411 and the smaller end diameter equal diameter portion. The outer diameter ratio B1 / B2 with respect to the outer diameter B2 is preferably 1.10 or more and 1.50 or less, and is about 1.27 in the third embodiment. Considering the case where the maximum outer diameter of the guide wire used for lower limb blood vessel treatment is 0.4572 mm (0.018 inch), the outer diameter ratio B1 / B2 is 1.10 or more and 1.80 or less. . When both cardiovascular treatment and lower limb vascular treatment are considered together, the outer diameter ratio B1 / B2 is 1.10 or more and 1.80 or less, preferably 1.15 or more and 1.80 or less. is there.
The reason for this is as follows.
When the core wire on the hand side is rotated, the torsional moment generated in the coil body 4 is proportional to the outer diameter ratio B1 / B2 of the rear end diameter large equal diameter portion 411 and the front end diameter small equal diameter portion 413. If the outer diameter ratio B1 / B2 falls below the lower limit value of 1.10, the torsional moment from the proximal side to the distal end side becomes low, and the guide wire is restrained to pass within the lesioned part of the stenosis or completely occluded lesion. It will be difficult. Moreover, if the outer diameter ratio B1 / B2 exceeds the upper limit value 1.80, the diameter do of the strands 8A and 8B must be reduced, and if the diameter is reduced, the torsional strength is insufficient.
Therefore, considering the area to be treated, the inner diameter of the blood vessel, and the practical dimensions of each medical device used for the diameter expansion treatment, the outer diameter ratio B1 / B2 is 1.10 or more and 1.80 or less, preferably 1.15. It is above 1.80.

Next, torsional stress and initial tension of the coil body 4 will be described.
Assuming that the torsional stress of the tightly wound portion 42B of the second coil body 42 having the same diameter portion 411 at the rear end is τ11, the torsional stress τ11 is the same as the torsional stress τ1 of the first embodiment, and is about 163.4 N / a mm ^2. Assuming that the initial tension of the densely wound portion 42B is F11, the initial tension F11 is the same as the initial tension F1 of the first embodiment and is about 5.13 × 10 ⁻² N.
When the outer diameter B2 of the tip of the closely wound portion 42B of the intermediate taper portion 412 is 0.260 mm, the torsional stress τ12 of the closely wound portion 42B is about 220.9 N / mm ² . Since the spring index C12 at the tip is about 3.33, when the torsional stress τ12 of this value is set to τ, and the spring index C12 is set to C, the range of the upper and lower limit values of the torsional stress τ is calculated. Is about 125.6 N / mm ² or more and 241.7 N / mm ² or less, and the torsional stress τ 12 is within this range. Similarly, the relational expression (5) is also satisfied.
The torsional stress τ12 of the closely wound portion 42B of the intermediate taper portion 412 is about 163.4 N / mm ² and about 220.9 N / mm ² at the rear end and the front end, and gradually increases from the rear end side to the front end side. .

When the initial tension of the closely wound portion 42B of the intermediate taper portion 412 is F12, when the torsional stress τ12 at the tip is about 220.9 N / mm ² , the diameter do of the core wire 8B is 0.060 mm and the coil average diameter Bo2 is Since it is 0.200 mm, the initial tension F12 at the tip is about 9.36 × 10 ⁻² N from the relational expression (7). Further, since the initial tension F12 at the rear end of the closely wound portion 42B of the intermediate taper portion 412 is the same as the initial tension F1 of the rear end diameter large-diameter portion 411, it is about 5.13 × 10 ⁻² N. is there.
Accordingly, the initial tension F12 of the tightly wound portion 42B of the intermediate taper portion 412 is about 5.13 × 10 ⁻² N to about 9.36 × 10 ⁻² N from the rear end to the front end, and from the rear end side to the front end side. Gradually increases. This means that a large initial tension F12 acts on the closely wound portion 42B of the intermediate taper portion 412 gradually from the rear end side to the front end side, and the adhesion force (compression force) between the coil wires is stronger toward the front end side. It means that.

  Then, the tightly wound portion 42B on which the initial tension F12 that gradually increases from the rear end side to the front end side acts on the outer side of the state-of-the-art second truncated cone having the smallest diameter among the connected truncated cones 26. The second coil body 42 of the intermediate taper portion 412 is disposed.

According to the third embodiment, the core wire on the proximal side is rotated by setting the "rear end diameter large equal diameter part, intermediate taper part, front end diameter small equal diameter part" from the rear end side toward the front end side. In this case, it is possible to improve the rotation transmission performance to the tip side.
The reason for this is that the torsional moment is proportional to the outer diameter ratio of the rear end diameter large equal diameter portion 411 and the front end diameter small equal diameter portion 413. Therefore, the rear end side outer diameter is increased and the front end side is decreased. This is because the rotation transmission performance to the distal end side is improved corresponding to the outer diameter ratio.

And the 2nd coil body 42 raises torsional stress, and when the core wire by the side of the hand side is rotated by providing the densely wound part 42B where high initial tension acts, the rotation transmission performance to the tip side is provided. It can be improved further.
Further, the tightly wound portion 42B on which the initial tension F12 gradually increasing from the rear end side toward the distal end side acts on the outer side of the thinnest second truncated cone 26B having a small diameter gradually decreasing toward the distal end side. By disposing the second coil body 42 of the intermediate taper portion 412, it is possible to supplement the effect of improving the rotation transmission to the tip side by the initial tension acting on the densely wound portion 42 </ b> B.
The reason is that the tightly wound portion where the initial tension F12 that gradually increases and increases toward the distal end acts on the outer side of the small second truncated cone 26B whose outer diameter gradually decreases from the rear end to the distal end. By arranging the second coil body of the intermediate taper portion 412 of 42B, the torsion angle is proportional to the torsional stress. Therefore, if the torsional stress increases, the torsional angle on the proximal side decreases, and the torsional angle on the proximal side decreases. This is because it complements the action. Also, if the torsional stress is increased, the initial tension is proportional to the torsional stress, so that the close contact force (compression force) due to the high initial tension acts between adjacent coil wires, and this strong contact force causes the hand side to rotate. Complements the effect of improving the rotation transmission performance to the tip side.

In particular, the second coil body of the intermediate tapered portion 412 is disposed outside the second truncated cone 26B, and the outer diameter of the core wire of the second truncated cone 26B gradually decreases toward the tip side. Then, by gradually increasing the initial tension of the densely wound portion 42B of the second coil body 42 toward the distal end side, both the twist angle decreasing effect on the proximal side and the torsional moment increasing effect on the distal end side are complemented. This is because these effects can be further enhanced.
Furthermore, the strand 8B used for the densely wound portion 42B of the second coil body 42 is formed by winding using an austenitic stainless steel wire having a mirror-like appearance so that the adjacent wires 8B are mirror-like, and This is because, since they are the same material, a strong adhesion force acts between adjacent strands 8B, the friction coefficient increases, and the complementary effect of improving the rotation transmission performance to the tip side can be further enhanced. According to this method, the function of complementing the improvement of the rotation transmission performance to the distal end side is exhibited by providing the tightly wound portion where the initial tension acts on at least the outside of the connecting truncated cone 26. The same applies to the first embodiment.

  If it supplements, the closely wound part which initial tension will act on the rear end side of the coil bodies 3 and 4 will be provided, and the coil pitch is less than twice the diameter of the coil wire in the loosely wound part on the front end side (the coil pitch is the strand). By setting the diameter do of 8A and 8B to 1.05 times or more and 1.90 times or less, it is possible to prevent the two guide wires from being bitten in the “parallel wire procedure”. The “parallel wire technique” here refers to the first guide wire inserted into the lesioned part, the first guide wire as a route guide, and another second guide wire introduced later. 2 This refers to a procedure that uses a guide wire to capture a blood passage (true lumen) that should normally pass into the lesioned part and to penetrate the blocked part. Accordingly, when the second guide wire is introduced using the first guide wire as the road guide, if the gap to of the strand 8A is larger than the diameter do of the strand 8A, the gap 8 to the gap 8A of one of the guide wires. The wire 8A of the other guide wire bites in and the biting phenomenon is likely to occur. This biting phenomenon can be prevented.

DESCRIPTION OF SYMBOLS 1,10 Medical guide wire 2 Core wire 2A Core wire rear end part 2B Core wire front end part 3, 4 Coil body 5A Front end joint part 5B Rear end joint part 5C Intermediate joint part 6 Fluoro resin film 7 Hydrophilic resin film 26 Connection truncated cone Body 26A first truncated cone 26B second truncated cone 26C third truncated cone 260 virtual single truncated cone

Claims (3)

Insert the core wire tip portion of the core wire having a portion that gradually changes from the rear end side to the tip side into the coil body,
The medical body in which the rear end of the coil body and the rear end of the core wire front end are joined by a rear end joint, and the front end of the coil body and the front end of the core wire front end are joined by a rounded tip joint . A guide wire,
The coil body is provided with a tightly wound portion on which a distal end side is wound with a radiopaque wire, a rear end side is wound in a twisted form with a radiation transmitting wire, and an initial tension acts on the coil body,
The core wire distal end portion of the coil body, tensile strength using an austenitic stainless steel wire of 3500 N / mm ² from 2200N / mm ^2, the rear end is in a truncated cone, at least 2 from the rear end to the front end side has a connecting truncated cones that by concatenating pieces or more of the truncated cones in the longitudinal direction, the longitudinal length of one of said truncated cone, the tip side from the truncated cones of the rear end Gradually decreasing toward the truncated cone,
The second moment of articulation truncated cone, gradual change decreased toward the rear end or et distal end side, and one which connects with a straight line the maximum outer diameter and the minimum outer diameter of the connecting truncated cones Is a virtual single truncated cone, the cross-sectional second moment of the articulated truncated cone at an arbitrary position in the longitudinal direction is the virtual single truncated cone at the same position as an arbitrary position in the longitudinal direction. Larger than the moment of inertia of the truncated cone ,
Close coiled portion of the coil body, a tensile strength using a wire of 3500 N / mm ² of austenitic stainless steel from 2200N / mm ^2, to lower the spring index of the front end side than the rear end side, said connecting截Placed outside the head cone,
The initial tension of the tightly wound portion of the coil body gradually increased from the rear end side to the front end side as the secondary moment of section of the articulated truncated cone gradually decreased from the rear end to the front end side . A medical guide wire characterized by the above. The densely wound portion of the coil body has a mirror-like appearance of the coil wire, a spring index C of 2.5 to 6.8 from the rear end side to the front end side, and a torsional stress due to initial tension τ (N / mm ² ) where the torsional stress τ (N / mm ² ) satisfies the relational expression of (−21.8C1 + 198.1) ≦ τ1 ≦ (−38.7C1 + 370.6). And an intermediate taper part and a small diameter part with a small tip diameter,
The intermediate taper portion is disposed outside the most distal truncated cone, and the initial tension of the tightly wound portion of the intermediate taper portion is gradually increased from the rear end side to the front end side. The medical guide wire according to 1. 3. The medical guide wire according to claim 2, wherein when the spring index C at the rear end of the intermediate taper portion is 4.50 and the spring index C at the small diameter portion at the tip is 3.33, the intermediate taper the initial tension of the close coiled portion of the tapered portion, 5.13 × ^{10 -2} from the rear end side from the N to 9.36 × ^{10 -2} N characterized in that by gradual change increases distally medical guide Wire.

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