JP2015047500A - Medical guide wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a medical guide wire that improves rotation transmission performance to a distal end side of the medical guide wire and plastic deformation performance, and prevents a jamming phenomenon of coils in a parallel wire procedure.SOLUTION: An outer coil 13 is joined to a distal end of a core wire 11. A spring index C1 in the outer coil 13 and a torsional stress τ1 of an outer densely wound portion 13B are made to be within a constant range. An initial tension F1 of the outer densely wound portion 13B on a proximal side is increased so that rotation transmission performance to a distal end side is improved even when a coarsely wound portion is provided on the distal end side. A coil pitch Po of an outer coarsely wound portion 13A is made to be less than 2 times a diameter do of element wires 8A so that plastic deformation performance is improved, and coils are prevented from engaging with each other.

Description

  The present invention relates to a medical guide wire used for the treatment of vascular lesions and the like.

  Conventionally, a medical guide wire (hereinafter simply referred to as a guide wire) has been used for diameter expansion treatment of a vascular lesion such as a vascular occlusion or stenosis. This guide wire includes one having a single coil at the distal end portion of the core wire, and one having an inner coil and an outer coil coaxially at the distal end portion of the core wire. By using these guide wires, the distal end portion is inserted into the blood vessel, and the inside of the blood vessel is advanced until it reaches the distal end portion, thereby performing diameter expansion treatment of the vascular lesion.

  In such a case, the guide wire needs to have optional performance, plastic deformation performance, and rotation transmission performance in order to improve the passage performance at the vascular lesion site. The optional performance refers to the performance of progressing in an arbitrary direction in a blood vessel or a branched blood vessel portion of a complicated path with a winding path. Plastic deformation performance refers to the performance of plastic deformation by bending the forefront part into a “h” shape. The rotation transmission performance refers to the performance of rotating the distal end portion through a coil partially fixed to the core wire together with the inserted core wire by rotating the hand portion (rear end portion) located outside the body.

  Patent Document 1 describes a guide wire in which a densely wound portion is provided at the center of a coil and a loosely wound portion is provided at both ends of the densely wound portion.

  Patent Document 2 describes a guide wire having a double structure in which an outer coil is arranged concentrically with an inner coil on the outer side of an inner coil having a core wire inserted therethrough.

JP 2010-0222 A JP-A-8-317989

  However, Patent Document 1 prevents unevenness of the resin coating when the outer periphery of the coil is coated with resin by providing a loosely wound portion at both ends of the coil and applying an initial tension to the densely wound portion at the center. However, other plastic deformation performance, optional performance and rotation transmission performance are not considered.

  In Patent Document 2, the rotation transmission performance of the guide wire is improved by using a radiopaque material for the inner coil, using stainless steel, a shape memory alloy or the like for the outer coil, and mainly using an elastic material for a spring for the core wire. However, there is a demand for comprehensively improving other plastic deformation performance, optional performance, and rotation transmission performance.

  This invention is made | formed in view of the said subject, and it aims at providing the medical guide wire which can improve the arbitrary selection performance in a branch blood vessel part, and the passage performance in a lesioned part.

To achieve the above objective,
A core wire with a large diameter at the hand side and a gradually changing diameter toward the tip ,
Austenitic stainless steel with a front end side spirally wound with a radiopaque strand, a rear end side having a strand diameter of 0.055 mm to 0.090 mm, and a tensile strength of 2200 MPa to 3500 MPa with a mirror appearance Wind the wire strands in a spiral,
Outside the front end portion of the core wire, the front end is provided at the front end of the core wire, and the rear end is joined to the front end portion of the core wire,
The outer coil has an outer loosely wound portion having a coil pitch of 1.05 times or more and 1.90 times or less of the wire diameter on the front end side, and a spring index C1 of 2.8 or more and 6.8 or less on the rear end side. When the torsional stress due to initial tension is τ1 (N / mm ² ),
And 11.2C1 + 111.7 ≦ τ1 ≦ −38.7C1 + 370.6 , which has an outer densely wound portion where the coil pitch is dense and the initial tension acts .

Said outer closed winding unit is characterized in that argument ChoTsutomu of is formed by strands of the following austenitic stainless steel wire 3500MPa or more 2200 MPa. Thus, the outer closed winding unit, condensation径伸beam machining, or tensile strength to be able to easily improved by combining the heat treatment the reduced径伸beam machining, and high to obtain a high modulus of transverse elasticity This is because torsional stress can be obtained. Furthermore, in the correlation between a spring index and a torsional stress described later, the torsional stress can be improved and the rotation transmission performance to the tip side can be improved.

The strand of the austenitic stainless steel wire used for the outer densely wound portion is characterized in that the appearance is a mirror surface . Further, it is characterized by having an outer densely wound portion that is spirally wound and has a dense coil pitch and an initial tension. It said outer closed winding portion, when forming by winding a wire of austenitic stainless steel wire helically, because molded winding provided negative coil pitch can not wire is free to rotate It is wound and formed in a twisted form. Thus, wherein the outer closed winding portion, acts initial tension, is wires together in contact next subjected to compressive force by the initial tension, frictional resistance is generated. Therefore, by making the appearance of the strands of the austenitic stainless steel wire used for the outer densely wound portion a mirror surface, the adjacent strands are mirror-like and of the same material. Since the strong adhesion force acts and the frictional resistance increases together with the initial tension , the rotation transmission performance to the tip side can be improved.

Before Kisotogawa closed winding portion is a spring index C1 is 2.8 to 6.8 or less, the torsional stress due to the initial tension when the ^{τ1 (N / mm 2),} -11.2C1 + 111.7 ≦ τ1 ≦ - It satisfies the expression 38.7C1 + 370.6. As a result, a high torsional stress can be obtained in the outer densely wound portion and a high initial tension can be applied, and even the coil having a loosely wound portion on the tip side can improve the rotation transmission performance to the tip side. .

Before Kisotogawa open coiled portion, the coil pitch and wherein 1.90 times or less der Rukoto 1.05 times the strand diameter. The rear end side of the outer coil consists of an outer densely wound portion where high torsional stress is applied and a high initial tension acts, and the tip side consists of an outer loosely wound portion whose coil pitch is less than twice the strand diameter. with the structure of dense winding portion and the outer open coiled portion, it is possible to prevent the phenomenon biting to pressed into the gap between the strands of the two guide wires during the parallel wires procedure described below.

Before Kisotogawa coil, from the rear side to the distal side, outside large diameter and the like diameter, outer intermediate tapered portion, have a outer diameter such diameter, Do1 the outer diameter of the outer diameter or the like diameter, said The outer diameter ratio (Do2 / Do1) is 1.10 or more and 1.80 or less when the outer diameter of the outer large diameter equal diameter portion is Do2. In this case, since the torsional moment is proportional to the outer diameter ratio of the outer large diameter equal diameter portion and the outer small diameter equal diameter portion, the outer diameter on the rear end side is enlarged, and the tip side is reduced in diameter. Corresponding to the outer diameter ratio, it is possible to improve the rotation transmission performance to the tip side by the rotation of the core wire on the hand side. Further, by providing the outer sparsely wound portion on the distal end side, it is possible to secure flexibility at the distal end, and to improve the “F” -shaped bendability and plastic deformation performance. Therefore, it is possible to improve the selectivity of a desired lesioned blood vessel at the branching blood vessel part to the lesioned part and the passage through the lesioned part.

According to the present invention, the Jiri stress tau 1 ne field ne index C 1 and the outer close coiled portion of the outer coil and a range, the effect of high initial tension F 1 to obtain a high torsional stresses on the outside close coiled portion And when a strong adhesion force acts between adjacent wires of the coil and the frictional resistance force is increased in combination with the initial tension, even when a loosely wound portion is provided on the tip side, The performance of transmitting rotation to the tip side can be further improved. Further, by the coil pitch of the outer open coiled portion is less than twice the iodine Senjika size, it improves the plastic deformation performance, the combination of the outer close coiled portion which initial tension acting parallel wires procedure described below It is possible to prevent the two guide wire coils from biting into each other.

It is a side view which cuts and shows a part of medical guidewire of 1st Embodiment of this invention. It is a side view which shows each part dimension of the principal part of the medical guide wire of the embodiment. It shows the correlation between the torsional stress and the spring index of the outer coil. It is sectional drawing of the evaluation apparatus used in order to evaluate the medical guide wire of this invention. The characteristic view of the medical guide wire of this invention is shown. It is a side view which shows each part dimension of the principal part of the medical guide wire of 2nd Embodiment.

(First embodiment)
As shown in FIG. 1, the guide wire 10 includes a core 11, an outer coil 13, and a joint portion 15A, 15 B, 1 5D joining the these. The core wire 11 is made of stainless steel or Ni—Ti alloy. For example, as described in JP-A-2002-69586, the core wire 11 made of high-strength stainless steel is manufactured by repeating the wire drawing treatment and the annealing treatment. Alternatively, as described in JP-A-2002-69555, the Ni-Ti alloy core wire 11 is manufactured by performing heat treatment under predetermined conditions. Note that the guide wire 10 of the present invention has a very small diameter compared to the length. For this reason, the guidewire 10 of the present invention is difficult to show in a predetermined area when the vertical and horizontal scale ratios are the same, and therefore, a part thereof is exaggerated or omitted.

The core wire 11 includes, in order from the hand side, a first equal diameter portion 11A, a first taper portion 11B, a second equal diameter portion 11C, a second taper portion 11D, a third equal diameter portion 11E, a third taper portion 11F, and a fourth. It has an equal diameter portion 11G. The core 11 has an outer diameter that decreases from, for example, 0.3556 mm (0.014 inch for cardiovascular treatment) to 0.060 mm as it goes from the proximal side to the distal end . A fluororesin film 16 is formed on the outer periphery of the large-diameter portion on the proximal side of the core wire 11 by coating or the like.

  The outer coil 13 uses an element wire 8A such as a radiopaque platinum wire or an alloy wire of platinum and nickel on the front end side, and an element wire 8B made of a radiolucent austenitic stainless steel wire on the rear end side. A coil formed by winding the wires 8A and 8B. The outer coil 13 is formed into one or a plurality of cylinders using one or a plurality of strands 8A and 8B. The winding direction of the strands 8A and 8B of the outer coil 13 is, for example, Z-winding (right-handed screw direction in Z notation).

The outer coil 13, the third and the like diameter portion 11E, in a state where the third tapered portion 11F, and the fourth like-diameter portion 11G is inserted, the junction of the distal end of the previous end of the core wire 11 (hereinafter, the tip joint hereinafter) joint 15A and the rear end (hereinafter, by the) 15B that rear end joint, is joined to the core 11. The distal end joint portion 15 </ b> A has a tip-round shape with a distal end rounded in an arc shape like a hemispherical shape, for example, and is provided at the most distal portion of the guide wire 10.

  The rear end joint portion 15B is provided in the third constant diameter portion 11E having an outer diameter of 0.160 mm or more and 0.190 mm or less. A hydrophilic resin film 17 is formed on the outer periphery of the outer coil 13, the outer periphery of the front end joint portion 15A, and the outer periphery of the rear end joint portion 15B by coating or the like.

  As shown in FIG. 2, the outer diameter Do of the outer coil 13 is 0.300 mm or more and 0.3556 mm or less, and is 0.325 mm in this embodiment. The length (full length) Lo in the core line direction of the outer coil 13 is not less than 100 mm and not more than 300 mm, and is 160 mm in the present embodiment. The diameter do of the strands 8A and 8B of the outer coil 13 is 0.055 mm or more and 0.090 mm or less, and is 0.060 mm in this embodiment. In consideration of the case of using for relatively large blood vessel treatment such as for treatment of the lower limb vascular occlusion, the diameter do of the strands 8A and 8B of the outer coil 13 is 0.090 mm. The coil average diameter Dao of the outer coil 13 is 0.265 mm because the outer diameter Do is 0.325 mm and the diameter do of the strands 8A and 8B is 0.060 mm.

Outer coil 13 has the open coiled portion of the previous end and the (outer open coiled portion) 13A, close coiled portion of the rear end of the (outer close coiled portion) 13B.

  The outer densely wound portion 13B is formed of an austenitic stainless steel wire 8B having a tensile strength of 2200 MPa to 3500 MPa. Since the outer densely wound portion 13B is formed of an austenitic stainless steel wire, the tensile strength can be easily improved by combining reduced diameter drawing or reduced diameter drawing and heat treatment, and High torsional stress can be obtained with high transverse elastic modulus. Furthermore, an austenitic stainless steel wire having a tensile strength of 2200 MPa or more and 3500 MPa or less is produced by repeating cold wire drawing and heat treatment as described in, for example, JP-A-2002-69586. Thereby, in the correlation between the spring index and the torsional stress, which will be described later, the torsional stress can be improved and the rotation transmission performance to the tip side can be improved. More preferably, the outer densely wound portion 13B is formed of an austenitic stainless steel wire having a mirror-like appearance. Here, when forming the outer densely wound portion 13B by spirally winding the austenitic stainless steel wire 8B, a negative coil pitch is provided and the wire 8B freely rotates. It is not possible to wind it in a twisted form. For this reason, in the outer densely wound portion 13B, adjacent wires 8B receive a compressive force due to the initial tension F1, and a frictional resistance force is generated. Therefore, by forming the outer densely wound portion 13B with an austenitic stainless steel wire having a mirror-like appearance, the adjacent strands 8B are mirror-like and made of the same material. Since the strong adhesion force acts and the frictional resistance force increases, the rotation transmission performance to the tip side can be improved. Here, the mirror-like shape means a surface shape such that unevenness cannot be detected by visual observation and tactile sensation, or light is reflected.

  The length LoA of the coil formed by winding the wire 8A on the distal end side of the outer coil 13 is not less than 30 mm and not more than 60 mm, and is 40 mm in this embodiment. The outer sparsely wound portion 13A is provided in a range of at least 20 mm from the inner side to the proximal side of the rounded tip joint portion 15A. In the present embodiment, the coil formed by winding the wire 8A on the distal end side of the outer coil 13 is the outer loosely wound portion 13A over the entire length. Therefore, a coil obtained by winding and forming the wire 8A on the distal end side of the outer coil 13 will be described as an outer loosely wound portion 13A. The length LoB of the coil formed by winding the wire 8B on the rear end side of the outer coil 13 is not less than 90 mm and not more than 180 mm, for example, 120 mm. In the present embodiment, the coil formed by winding the wire 8B on the rear end side of the outer coil 13 is the outer densely wound portion 13B over the entire length. Therefore, the coil formed by winding the wire 8B on the rear end side of the outer coil 13 will be described as the outer densely wound portion 13B. Therefore, the outer densely wound portion 13B is 3/5 or more of the length of the outer coil 13 in the core line direction.

The outer loosely wound portion 13A and the outer densely wound portion 13B are joined at a joining portion 15D (hereinafter, referred to as an intermediate joining portion 15D) between the leading end and the trailing end of the leading end portion of the core wire 11. The intermediate joint 15D is made of a brazing material such as solder or another joining member. At the time of joining, a part of the strand 8A of the outer loosely wound portion 13A and a portion of the strand 8B of the outer densely wound portion 13B are screwed, a brazing material is put into the screwed portion, and both the strands are joined. A method of joining by welding or the like is used.

  The coil pitch Po of the outer loosely wound portion 13A is less than twice the diameter do of the wire 8A, and is 1.05 times or more and 1.90 times or less of the diameter do of the wire 8A. .25 times. In this embodiment, since the diameter do of the strand 8A is 0.060 mm, 1.25 times that is the coil pitch Po, which is 0.075 mm.

Next, the relationship between the torsional stress τ (τ 1) and the spring index C (C 1) will be described with reference to FIG. As shown in FIG. 3, L1, L3, and L4 are approximate expressions when the spring index is 2.8 or more and 6.8 or less, and this range is a solid line and the outside of the range is a dotted line. L2 is an approximate expression when the spring index is 3.5 or more and 5.5 or less, and the inside of this range is a solid line and the outside of the range is a dotted line.

FIG. 3 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 and the vertical axis is the torsional stress τ (N / mm ² ). Such a relationship between the torsional stress τ (N / mm ² ) and the spring index C is derived from the result of a test performed in advance. Spring index C1 of the outer coil 13 is 2.8 or more 6.8 or less, in the present embodiment Ru about 4.42 der.

The spring index C1 of the outer closed winding portion 13B is taken as 2.8 to 6.8 or less, the torsional stress tau 1 of the outer closed winding portion 13B, it is preferable to satisfy the following formula (1). (Indicated symbols L1 and L4)
−11.2C1 + 111.7 ≦ τ1 ≦ −38.7C1 + 370.6 (1)

Torsional stress tau 1, but if less than the lower limit of the above formula (1), the rotation transmission performance is lowered into the outer closed winding portion 13 B or al front end side of the rear end. When torsional stress tau 1 exceeds the upper limit of the above formula (1), the rigidity changes that occur at the boundary between the outer close coiled portion 13 B and the outer open coiled portion 13 A, the radius of curvature at the boundary or the like toward the distal end side The gradual change is not reduced, and a sudden bending is likely to occur, and the rotation transmission performance to the tip side is deteriorated. Accordingly, while preventing a local deformation by kinking, considering that to prevent a decrease in the rotation transmission performance distally, torsional stress τ1 outer closed winding portion 13B is that meet the above formula (1) preferable.

More preferably, when the spring index C 1 of the outer closed winding portion 13 B is 2.8 or more 6.8 or less, the torsional stress tau 1 of the outer closed winding portion 13B, it satisfies the following formula (2) preferable. (Indicated symbols L1 and L3)
−21.8C1 + 198.1 ≦ τ1 ≦ −38.7C1 + 370.6 ( 2 )

The bending deformation due to kinking in the boundary or the like between the outer closed winding portion 13 B and the outer open coiled portion 13 A with more prevented more the rotation transmission performance of the outer closed winding portion 13 B or al outer open coiled portion 13 A considering that improved torsional stress τ1 outer closed winding portion 13B is more preferably plus above formula (2) fully.

More preferably, when the spring index C 1 of the outer closed winding portion 13 B and 3.5 to 5.5, the torsional stress tau 1 of the outer closed winding portion 13B preferably satisfies the following formula (3) . (Indicated symbols L1 and L2)
−30.9C1 + 280.4 ≦ τ1 ≦ −38.7C1 + 370.6 (3)

The torsional stress τ1 of the outer densely wound portion 13B is about 143.8 N / mm ² or more and about 199.5 N / mm ² or less based on the above formula (3) because the spring index C1 is about 4.42. There, in the present embodiment Ru about 166.5N / mm ² der.

Next, the relationship between the torsional stress τ and the initial tension F of the outer densely wound portion 13B will be described.

The initial tension F (N) is represented by the following formula ( 4 ). Here, d is the wire diameter, τ is the torsional stress, and Da is the coil average diameter.
F = πd ³ τ / (8 Da) ( 4 )

The initial tension F is provided by forming by winding with a negative coil pitch when forming the wire by spirally winding it. Therefore, the initial tension F can be increased or decreased by increasing or decreasing the negative amount of the negative coil pitch. Thereby, the torsional stress tau 1 of initial tension F1 of the outer closed winding portion 13 B, the correlation between the outer open coiled portion 13 A, or higher, can be adjusted or lowered.

Initial tension F1 of the outer side close coiled portion 13B, the diameter do of the wire 8B of the outer coil 13 is 0.060 mm, torsional stress τ1 is 166.5N / mm ² of the outer closed winding portion 13B, the coil average of outer coil 13 the diameter Dao is a 0.265 mm, based on the equation (4), Ru about 5.33 × 10 ■ ² N der.

Next, the evaluation device 18 used to evaluate the spring index C (C 1) and the deformation rate (%) when the spring index C 1 of the outer coil 3 is changed will be described.

  As shown in FIG. 4, the evaluation device 18 includes an inlet portion 18a and a bent meandering portion 18b. The inlet portion 18a has an inner diameter ID1 of 2 mm. The bent meandering portion 18b has an inner diameter ID2 of 0.5 mm. The bending meandering part 18b is provided with six 180 degree bending parts 18c having a radius r1 of 5 mm. This evaluation device 18 is formed of a resin tube.

Here, the deformation occurrence rate (%) is the plastic deformation obtained by repeatedly inserting each test product of the outer coil 3 into the evaluation device 18 20 times and then evaluating the insertion characteristics and the rotation transmission performance. Defect occurrence rate (%).

As shown in FIG. 5, the deformation rate (%) increases rapidly when the spring index C exceeds 6.8. On the other hand, when the spring index C is less than 2.8, the deformation rate (%) is likely to cause scales, cracks, etc. on the surface of the strands when it is formed by being spirally wound. Therefore, the spring index C (C1 ) of the outer coil 3 is 2.8 or more and 6.8 or less in consideration of the deformation occurrence rate, cracks, and the like of the outer coil 3 .

According to this embodiment, the spring index C 1及 Binejiri stress tau 1 of definitive to the outer coil 1 3 As certain range, by an increased initial tension F 1 of the rear end side of the outer closed winding portion 13B, the distal end side Even when a loosely wound portion is provided in the rotation transmission performance to the distal end side can be improved. Further, by setting the coil pitch Po of the outer loosely wound portion 13A to be less than twice the diameter do of the wire 8A, it is possible to improve the plastic deformation performance and prevent the coils from being bitten.

Ri by the the provision of the outer open coiled portion 13 A, the flexibility of the distal end portion of the gas guide wire 10 is maintained. Therefore, soft touch with the blood vessel wall is possible. Further, the "F" -shaped bending deformation can be easily performed, and the plastic deformation performance can be improved.

  The outer densely wound portion 13B is applied with a compressive force (adhesive force) due to the initial tension F1 between adjacent strands 8B, and the outer loosely wound portion 13A has a coil pitch Po and a diameter do (0.060 mm) of the strand 8A. The size is less than twice (0.120 mm) (0.075 mm), and by using these together, the rotation transmission performance to the distal end side is improved, and two parallel guide wires are used by the operator. In the “wire method” procedure, the element of the outer sparsely wound portion 13A of the second guide wire introduced later into the gap to between the strands 8A of the outer sparsely wound portion 13A of the first guide wire previously inserted. The biting phenomenon that the wire 8A bites in can be prevented. The “parallel wire method” here refers to the method of inserting the first guide wire into the lesion and then introducing the second guide wire as the first guide wire. This refers to a technique in which a second guide wire is used to capture a blood passage (true lumen) that should originally pass through the lesioned part and to penetrate the blocked part. Therefore, when the second guide wire is introduced using the first guide wire as the road guide, if the gap to the strand 8A is larger than the diameter do of the strand 8A, the gap 8 to the strand 8A of one guide wire is moved to. The wire 8A of the other guide wire bites in and the biting phenomenon is likely to occur. The medical guide wire of the present invention can prevent this phenomenon, and the first guide wire and the second guide wire are not entangled.

  When the initial tension F1 is applied to the outer densely wound portion 13B, a compressive force is applied in advance between the strands 8B to increase the adhesion force. Therefore, when a tensile force is applied to the outer densely wound portion 13B. Until the adjacent wires 8B are separated (until the gap is opened), the initial tension F1 acts as a resistance force to the tensile force. Therefore, the rotation transmission performance to the tip side can be improved when the hand side is rotated.

The strand 8B of the outer closed winding portion 13B, by the appearance formed by using the mirror-like austenitic stainless steel wire, for the adjacent wires 8 B is a mirror-like, and the same material, adjacent since frictional resistance wire 8 B-phase each other strong adhesion force acts to increase, thereby improving the rotation transmission performance distally.

(Second Embodiment)
As shown in FIG. 1, the guide wire 10 of the first embodiment has the same outer diameter from the rear end side to the front end side of the outer coil 13, but the guide wire 20 of the second embodiment is similar to FIG. As shown in FIG. 4, the outer diameter of the outer coil 23 is gradually changed from the rear end side toward the front end side. Other configurations are the same as those in the first embodiment, and the same components are denoted by the same reference numerals and redundant description is omitted.

  The outer coil 23 has an outer loosely wound portion 23A and an outer densely wound portion 23B. The outer sparsely wound portion 23A is provided in a range of at least 10 mm from the inner side to the proximal side of the rounded tip joint portion 15A. The coil pitch Po of the outer sparsely wound portion 23A, the gap to of the wire 8A, the diameter do of the wires 8A and 8B, the material of the outer coil 23, and the outer coil 23 are wound with at least one wire 8A and 8B. The points formed in the cylinder are the same as in the first embodiment. Further, the outer sparsely wound portion 23A and the outer densely wound portion 23B are joined by the intermediate joint portion 15D as in the first embodiment.

Outer coil 23, outside large diameter, etc. diameter portion 31 from the rear end side in order, outer intermediate tapered portion 32, that have a outer diameter such diameter portion 33.

  The outer large diameter equal diameter portion 31 has an outer diameter Do2 of 0.325 mm and a coil average diameter Dao2 of 0.265 mm. The outer diameter of the outer intermediate taper portion 32 is gradually changed from 0.325 mm to 0.260 mm. The outer small diameter equal diameter portion 33 has an outer diameter Do1 of 0.260 mm and a coil average diameter Dao1 of 0.200 mm.

  The overall length Lo of the outer coil 23 is 155 mm. The length Lo1 of the outer large-diameter equal-diameter portion 31 is 120 mm. The length Lo2 of the outer intermediate taper portion 32 is 20 mm. The length Lo3 of the outer small diameter equal diameter portion 33 is 15 mm.

  The outer diameter ratio Do2 / Do1 between the outer diameter Do2 of the outer large diameter equal diameter portion 31 and the outer diameter Do1 of the outer small diameter equal diameter portion 33 is 1.10 or more and 1.50 or less. 1.25. 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 Do2 / Do1 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 Do2 / Do1 is 1.10 or more and 1.80 or less, preferably 1.15 or more and 1.80 or less. is there.

Torsional moment occurring to the outer coil 23 is proportional to the outer diameter ratio Do2 / Do1 the outside large diameters diameter portion 31 and the outer diameter or the like diameter portion 33. Therefore, if the outer diameter ratio Do2 / Do1 falls below the lower limit value 1.10, the torsional moment from the proximal side to the distal end side becomes low, and the guide wire is constrained to pass through the lesion tissue of the stenosis or the completely occluded lesion. Will be difficult. The outer diameter ratio Do2 / Do1 is if exceeds the upper limit 1.80, it is necessary to slender, leading to insufficient strength when slender. 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 Do2 / Do1 is 1.10 or more and 1.80 or less, preferably 1.15. It is above 1.80.

Next, the spring index C of the outer coil 23 and the torsional stress τ of the outer densely wound portion 23B will be described. The spring index C1 and the torsional stress τ1 of the outer densely wound portion 23B are the same as in the first embodiment.

Next, the initial tension F of the outer densely wound portion 23B will be described. The initial tension F1 of the outer densely wound portion 23B is the same as in the first embodiment.

According to the second embodiment, the shape of the outer coil 23 is changed from the rear end side toward the front end side as “ outer large diameter equal diameter portion, outer intermediate taper portion, outer small diameter equal diameter portion ”. The rotation transmission performance to the tip side by the rotation of the core wire can be improved. This is because the torsional moment is proportional to the outer diameter ratio of the outer large diameter equal diameter portion and the outer small diameter equal diameter portion, so if the outer diameter on the rear end side is increased and the front end side is reduced, the outer diameter is increased. The rotation transmission performance is improved corresponding to the diameter ratio. Furthermore, by kicking setting the outer open coiled portion 23 A of the outer coil 23, the effect of improving the crease resistance and plastic deformation performance of shaped "to" is obtained and ensures flexibility of the tip. Therefore, it is possible to improve the selectivity to a desired lesioned blood vessel at the branching blood vessel part to the lesioned part and to improve the inside of the lesioned part.

To form the outer side open coiled portion 23 A of the outer coil 23 easily, a plurality of wires 8 (8A, 8B) rather than a cylindrical using, with one strand 8 respectively It is desirable to form in a cylinder. When forming the outer open coiled portion 23 A by using a plurality of strands, the winding direction of the wire rewinds the wire in the opposite direction, must a clearance between the wires, It becomes difficult to make the gaps between the plurality of strands uniform. In addition, when joining to the core wire 11 using a brazing material or the like, particularly when joining at the intermediate portion in the core wire direction, it is necessary to provide a uniform gap between the strands at the intermediate portion of the coil, which is extremely difficult to process. It becomes difficult. On the other hand, in the case of a coil wound with one strand, the gap between the strands can be set arbitrarily by simply applying tension in the direction of the core wire, and the end portion or intermediate portion of the coil, etc. The gap between the strands can be adjusted at any of the locations.

Outer side open coiled portion 13A, 23A, the length core length of the outer closed winding portion 13B, 23 B may be changed as appropriate. The coil pitch Po of the outer open coiled portion 13A, may have a configuration in which by gradual change expanded toward the distal side.

Instead of the second taper portion 11D, the third constant diameter portion 11E, and the third taper portion 11F, from the end portion on the distal end side of the second constant diameter portion 11C toward the end portion on the proximal side of the fourth constant diameter portion 11G. You may provide the 4th taper part from which an outer diameter changes gradually. In this case, the outer coil 13 and 23, a fourth tapered portion rear end joint 15B is provided, Ru is bonded to the core wire 11 by the distal bonding portion 15A.

10, 20 Guide wire 11 Core wire 13, 23 Outer coil 23A Outer sparsely wound portion 23B Outer densely wound portion 16 Fluorine resin coating 17 Hydrophilic resin coating

To achieve the above object, the hand side is a large diameter, the tip comprises a core of gradually changing diameter toward the distal end, and an outer coil to the outside of the distal end portion of the core wire,
The outer coil, the front end side is an outer loosely wound portion, the rear end side is an outer densely wound portion,
The tip of the outer sparsely wound portion is joined to the tip of the core wire , and the rear end of the outer densely wound portion is joined to the tip of the core wire ,
The outer sparsely wound portion is formed by spirally winding a radiopaque strand so that the coil pitch is 1.05 times to 1.90 times the strand diameter ,
The outer densely wound portion is formed by spirally winding a strand of an austenitic stainless steel wire with a strand diameter of 0.055 mm to 0.090 mm and a tensile strength of 2200 MPa to 3500 MPa with a mirror-like appearance. It is a tightly wound part that is wound in a twisted form and receives initial tension,
When the spring index C1 is 2.8 or more and 6.8 or less, and the torsional stress due to the initial tension is τ1 (N / mm ² ),
−11.2C1 + 111.7 ≦ τ1 ≦ −38.7C1 + 370.6,
It is characterized in that the external appearance of the strands acts on the adjacent strands by a mirror-like adhesion force and a compressive force by the initial tension, thereby increasing the frictional resistance force between the adjacent strands .

The strand of the austenitic stainless steel wire used for the outer densely wound portion is characterized in that the appearance is a mirror surface. Further, the present invention is characterized in that an outer densely wound portion in which an initial tension acts is formed by spirally winding a strand having a mirror-like appearance and winding it in a twisted form . Furthermore, the appearance of the strands acts on the adjacent strands of the outer densely wound portion by applying the adhesion force due to the mirror surface and the compressive force due to the initial tension, thereby increasing the frictional resistance force between the adjacent strands. Features . When the outer densely wound portion is formed by spirally winding a wire of an austenitic stainless steel wire, a negative coil pitch is provided and the wire cannot be freely rotated. It is wound in a twisted form. For this reason, an initial tension acts on the outer densely wound portion, and the adjacent strands receive a compressive force due to the initial tension to generate a frictional resistance. Therefore, by making the appearance of the strands of the austenitic stainless steel wire used for the outer densely wound portion a mirror surface, the adjacent strands are mirror-like and of the same material. A strong adhesion force acts, and further, the friction resistance force between adjacent strands increases along with the action of the mutual compression force due to the initial tension , so that the rotation transmission performance to the tip side can be improved. it can.

According to the present invention, the spring index C1 of the outer coil and the torsional stress τ1 of the outer densely wound portion are set within a certain range, a high torsional stress is obtained on the outer densely wound portion, and a high initial tension F1 is applied. It acts strong adhesion force to a wire together and, by increasing more the frictional resistance of the wires mutually adjacent in conjunction with the action of the compression force due to initial tension, if the open coiled portion is provided on the distal end side Even so, the rotation transmission performance to the tip end side can be further improved. In addition, by making the coil pitch of the outer sparsely wound portion less than twice the wire diameter, the plastic deformation performance is improved, and in combination with the outer densely wound portion where the initial tension acts, the parallel wire procedure described later is performed. It is possible to prevent the two guide wire coils from being bitten by each other.

The initial tension F1 of the outer densely wound portion 13B is such that the diameter do of the strand 8B of the outer coil 13 is 0.060 mm, the torsional stress τ1 of the outer densely wound portion 13B is 166.5 N / mm ² , and the coil average diameter of the outer coil 13 since Dao is a 0.265 mm, based on the equation (4), about 5.33 × 10 ^- a ² N.

Claims (2)

A core wire with a large diameter at the hand side and a gradually changing diameter toward the tip,
Austenitic stainless steel with a front end side spirally wound with a radiopaque strand, a rear end side having a strand diameter of 0.055 mm to 0.090 mm, and a tensile strength of 2200 MPa to 3500 MPa with a mirror appearance Wind the wire strands in a spiral,
  Outside the front end portion of the core wire, the front end is provided at the front end of the core wire, and the rear end is joined to the front end portion of the core wire,
  The outer coil has an outer loosely wound portion having a coil pitch of 1.05 times or more and 1.90 times or less of the wire diameter on the front end side, and a spring index C1 of 2.8 or more and 6.8 or less on the rear end side. The torsional stress due to initial tension is τ1 (N / mm ² )
    A medical guide wire characterized by having an outer densely wound portion that satisfies a formula of 11.2C1 + 111.7 ≦ τ1 ≦ −38.7C1 + 370.6 and has a dense coil pitch and an initial tension. The outer coil has an outer large diameter equal diameter portion, an outer intermediate taper portion, and an outer small diameter equal diameter portion from the rear end side toward the distal end side, and the outer diameter of the outer small diameter equal diameter portion is Do1, 2. The medical guide wire according to claim 1, wherein the outer diameter ratio (Do2 / Do1) is 1.10 or more and 1.80 or less when the outer diameter of the large diameter equal diameter portion is Do2.

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