WO2024236761A1 - Blood vessel guide wire - Google Patents

Abstract

A guide wire 1 comprises: a core wire 10 extending from the rear end toward the tip end; a tip end part 111 provided at the tip end of the core wire 10 and formed in a flat plate shape; a first tapered part 112, a second tapered part 113, a third tapered part 114, and a fourth tapered part 115 that are continuously provided in four stages, that continue on from the rear end of the tip end part 111, and that have an outer diameter that increases from the tip end-side to the rear end-side; an X-ray visible coil 20 and a non-X-ray visible coil 30 that externally fit over the first tapered part to the fourth tapered part 115, which are continuously provided in at least four stages, and over the tip end part 111; and a securing part for securing the rear end of the non-X-ray visible coil 30 and the core wire, wherein the length of the tip end part 111 in the axial direction is 5 mm to 25 mm.

Description

Vascular Guidewire

This disclosure relates to a vascular guidewire.

Guidewires are used to deliver catheters and other items into blood vessels. Guidewires must be able to properly deliver catheters to the desired vascular location within blood vessels that are complexly bent and branched, and so flexibility is required, particularly at the tip. To increase flexibility near the tip of the guidewire, the tip is made thinner than the proximal side, and the small-diameter section is connected to the large-diameter section in a tapered shape (see, for example, Patent Document 1).

Furthermore, in order to select and advance a desired blood vessel at a branching point of blood vessels during operation within the cerebral blood vessels, shaping is performed by bending the tip of the guidewire into a desired shape in advance. Since shaping is performed manually, it is desirable for the tip of the guidewire to have good properties (hereinafter also referred to as shapeability) that allow it to be easily formed into a desired shape. Patent Document 1 also discloses that the tip is made thinner than the proximal side in order to increase flexibility near the tip.

JP 2021-142015 A

However, in the guidewire described in Patent Document 1, the core wire has a single tapered shape with the diameter narrowing from the rear end to the tip end. When the taper angle is small with a single tapered shape, the tip cannot be made sufficiently flexible. Also, when the taper angle is large with a single tapered shape, the tip becomes flexible but the middle section (between the tip and rear end) also becomes excessively thin, and there are cases where the pushing force is not sufficiently transmitted to the tip. It is desirable for a guidewire to have good pushing force transmission to the tip (hereinafter also referred to as pushability).

The objective of this disclosure is to provide a vascular guidewire that is highly flexible and has good shapeability and pushability.

The present disclosure solves the above problems by the following solutions. Note that, for ease of understanding, the following explanations are given with reference symbols corresponding to the embodiments of the present disclosure, but the present disclosure is not limited to these.

The first disclosure is a vascular guidewire (1) comprising a core wire (10) extending from the rear end to the front end, a front end portion (111) formed in a flat plate shape at the front end of the core wire, four or more consecutive tapered sections (112, 113, 114, 115) connected to the rear end of the front end portion (111) and having an outer diameter increasing from the front end side to the rear end side, a coil (20, 30) inserted around all of the four or more consecutive tapered sections (112, 113, 114, 115) and the front end portion (111), and a fixing section (F) that fixes the rear end of the coil (20, 30) to the core wire (10), and the axial length of the front end portion (111) is 5 mm or more and 25 mm or less.

The second disclosure is a vascular guidewire (1) according to claim 1, in which the fixing portion (F) is connected to the rear end of the tapered portion (112, 113, 114, 115) that is provided in four or more consecutive stages, and is provided on a cylindrical portion (116) that is formed into a cylindrical shape.

The third disclosure is a vascular guidewire (1) according to claim 1 or claim 2, in which the coils (20, 30) include at least an X-ray visible coil (20) extrapolated to the tip portion (111) and a non-X-ray visible coil (30) connected to the rear end of the X-ray visible coil (20).

The fourth disclosure is a vascular guidewire (1) according to claim 1 or claim 2, which is used in the carotid artery or cerebral blood vessels.

The present disclosure provides a vascular guidewire that is highly flexible and has good shapeability and pushability.

1 is a side view showing an embodiment of a cerebrovascular guidewire according to the present disclosure as viewed from the -Y side. FIG. FIG. 2 is a side view showing the configuration of the core wire 10 as viewed from the same direction as FIG. 1 . FIG. 3 is a side view showing the configuration of the core wire 10 as viewed from the +Z side in FIGS. 1 and 2 . 13 is a diagram for explaining that it is desirable for the length of the X-ray visible coil 20 in the axial direction to be 30 mm or more. FIG. FIG. 3 is an enlarged view of a range A1 in FIG. 2 . FIG. 4 is an enlarged view of a range A2 in FIG. 3. FIG. 4 is a view of the core wire 10 in the state of FIG. 3 as viewed from the tip side (+X side). FIG. 13 is a diagram showing the positional relationship between the X-ray visible coil 20 and the non-X-ray visible coil 30 and the core wire 10, with the X-ray visible coil 20 and the non-X-ray visible coil 30 partially not shown. 1A to 1C are diagrams illustrating an example of a method for shaping the distal end side of the guide wire 1 of this embodiment. 1A to 1C are diagrams illustrating a method for advancing a guidewire 1 within a cerebral blood vessel. FIG. 2 is a diagram showing an example of imaging of the guidewire 1. FIG. 2 is a diagram showing an example of imaging of the guidewire 1.

(Embodiment)
Hereinafter, one embodiment of the present disclosure will be described with reference to the drawings. Note that all of the drawings attached to this specification are schematic diagrams, and the shape, scale, aspect ratio, and the like of each part are modified or exaggerated from the actual product in consideration of ease of understanding, etc. For example, the longitudinal direction of the guidewire 1 is shown shorter and the radial direction is shown thicker.

In this specification and the like, terms specifying the shape, geometric conditions, and the degree of these, such as "parallel" and "direction", include the strict meaning of the term, as well as the range of the degree to which it can be considered to be approximately parallel and the range of the range that can be considered to be roughly in that direction. Furthermore, in this specification, the direction in which the imaginary central axis extends when the guidewire 1 is extended in a straight line is also referred to as the axial direction, and the XYZ Cartesian coordinate system with the X axis set in this axial direction is shown in the figures. The -X side is the proximal side (or rear end side) closer to the practitioner, and the +X side is the distal side (or tip side) farther from the practitioner.

FIG. 1 is a side view showing an embodiment of a cerebrovascular guidewire according to the present disclosure as viewed from the -Y side. FIG. 2 is a side view showing the configuration of the core wire 10 as viewed from the same direction as FIG. 1. FIG. 3 is a side view showing the configuration of the core wire 10 as viewed from the +Z side in FIGS. 1 and 2. In FIGS. 2 and 3, the X-ray visible coil 20, the non-X-ray visible coil 30, the solder used for joining, etc. are omitted, and only the core wire 10 inside them is shown.

As shown in FIG. 1, the guidewire 1 has a core wire 10, an X-ray visible coil 20 and a non-X-ray visible coil 30 that are extrapolated to the tip side of the core wire 10, and a tip fixing portion 40. It is a vascular guidewire that is inserted into cerebral blood vessels and can be suitably used for the carotid artery and cerebral blood vessels.

The X-ray visible coil 20 is a coil-shaped member formed by winding a linear body into a spiral and cylindrical shape. The X-ray visible coil 20 is extrapolated onto the tip side (+X side) of the first core wire 110. The X-ray visible coil 20 serves as a marker (sign) for confirming the position of the tip of the guide wire 1 in an X-ray transmission image. The X-ray visible coil 20 is made of a material that is opaque (including poorly permeable) to radiation such as X-rays and that can be formed into a coil shape. Examples of materials that form the X-ray visible coil 20 include platinum tungsten (Pt-W) alloy, platinum-iridium (Pt-Ir) alloy, gold, tantalum, etc.

The provision of the X-ray visible coil 20 at the tip of the guidewire 1 is important for performing the procedure of delivering the guidewire 1. By providing the X-ray visible coil 20 at the tip of the guidewire 1, the practitioner can grasp the direction of the tip of the guidewire 1 after it has been shaped within the blood vessel, and can advance the guidewire 1 in the appropriate direction.

The X-ray visible coil 20 is formed by a single linear body, with the first coarsely wound section 21, the densely wound section 22, and the second coarsely wound section 23, in order from the tip side in the axial direction. The first coarsely wound section 21 and the second coarsely wound section 23 are provided at the tip side and the rear end side of the densely wound section 22, respectively, and the linear body is wound more coarsely than the densely wound section 22. That is, the densely wound section 22 has a densely wound linear body, and the first coarsely wound section 21 and the second coarsely wound section 23 have a coarsely wound linear body. In this embodiment, the densely wound section 22 is tightly wound, and there is almost no gap between adjacent linear bodies in the axial direction, but a gap may be provided. Note that the reason why it is said that there is "almost no gap" (hereinafter the same) is that there may be gaps due to variations in the thickness of the linear body itself or manufacturing errors in the winding process. On the other hand, in the first coarsely wound portion 21 and the second coarsely wound portion 23, a gap is intentionally provided between adjacent linear bodies in the axial direction. Note that, although FIG. 1 shows the first coarsely wound portion 21 and the second coarsely wound portion 23 as being provided with about two turns, the first coarsely wound portion 21 and the second coarsely wound portion 23 can be provided with a greater number of turns. It is desirable for the X-ray visible coil 20 to have an axial length of 30 mm or more so that the shape of the tip portion 111 can be accurately grasped during treatment.

Figure 4 is a diagram explaining why it is desirable that the axial length of the X-ray visible coil 20 is 30 mm or more. When performing a procedure in which the guidewire 1 is advanced inside a blood vessel, it is desirable to be able to observe the blood vessel running when the guidewire 1 passes through a part of the blood vessel with a large curvature (small radius of curvature of the bend). In Figure 4, a part where the blood vessel B is bent 180° is shown as a schematic cross section. It is considered desirable to be able to observe the blood vessel running when the guidewire 1 passes through even a part with the smallest radius of curvature where the blood vessel is bent 180° as shown in Figure 4. It is known that the radius of curvature RB at the center of the blood vessel in the part with a high degree of tortuosity in the carotid artery and cerebral blood vessels is about 2.7 mm. In a situation where the blood vessel B is bent 180° as shown in Figure 4, the length of the center line BC at the part where the blood vessel B is bent 180° is 2 x π x 2.7 ≒ 17 mm. The inner diameter of the blood vessel is about 3 mm to 5 mm. From these conditions, the length of the outer curve of the inner surface of the blood vessel along which the guidewire 1 is expected to pass (the length of the inner surface BL in FIG. 4) is calculated by 2×π×(2.7+3/2) to 2×π×(2.7+5/2), which is approximately 26 mm to 33 mm. Therefore, it is desirable that the axial length of the X-ray visible coil 20 is 30 mm or more in order to be able to accurately grasp the shape of the tip portion 111 during treatment. It is even more desirable that the axial length of the X-ray visible coil 20 is 40 mm or more. It is also desirable that the axial length of the X-ray visible coil 20 is 60 mm or less.

The non-X-ray visible coil 30 is a coil-shaped member formed by winding a linear body into a spiral and cylindrical shape, similar to the X-ray visible coil 20. The non-X-ray visible coil 30 is inserted onto the core wire 10 at the tip side (+X side) of the first core wire 110 and the rear end side of the X-ray visible coil 20. By inserting the non-X-ray visible coil 30 onto the tip side of the first core wire 110, a reinforcing effect is obtained that makes the first core wire 110 less likely to break, while allowing it to bend moderately without losing flexibility. Examples of materials for forming the non-X-ray visible coil 30 include stainless steel, tungsten, nickel-titanium alloy, etc.

The non-X-ray visible coil 30 is formed by a single linear body, with the first coarsely wound section 31, the densely wound section 32, and the second coarsely wound section 33, in that order from the tip side in the axial direction. The first coarsely wound section 31 and the second coarsely wound section 33 are provided at the tip side and rear end side of the densely wound section 32, respectively, and the linear body is wound more coarsely than the densely wound section 32. That is, the linear body is densely wound in the densely wound section 32, and the linear body is wound coarsely in the first coarsely wound section 31 and the second coarsely wound section 33. In this embodiment, the densely wound section 32 is tightly wound, and there is almost no gap between adjacent linear bodies in the axial direction, but a gap may be provided. On the other hand, in the first coarsely wound section 31 and the second coarsely wound section 33, a gap is intentionally provided between adjacent linear bodies in the axial direction. In FIG. 1, the first coarsely wound portion 31 and the second coarsely wound portion 33 are shown as having about 2 to 4 turns, but the first coarsely wound portion 31 and the second coarsely wound portion 33 can be provided with a larger number of turns. The length of the non-X-ray visible coil 30 is preferably 150 mm or more and 350 mm or less.

As shown in FIG. 1, a roughly hemispherical tip fixing portion 40 is provided further toward the tip side (+X side) than the X-ray visible coil 20. The tip fixing portion 40 may be in the form of a roughly hemispherical component attached, or the tip fixing portion 40 may be formed of the solder itself by dropping an appropriate amount of solder onto the tip side of the X-ray visible coil 20. The shape of the tip fixing portion 40 is not limited to a roughly hemispherical shape, and may be other shapes, such as a part of an ellipsoid. Solder is just one example and is not limiting.

The tip side of the X-ray visible coil 20 (part of the first coarsely wound portion 21) is soldered to the tip portion 111 (described below) of the first core wire 110 together with the tip fixing portion 40, or by the tip fixing portion 40 if the tip fixing portion 40 is formed by solder itself. The solder in this portion fills the gaps in the first coarsely wound portion 21. Furthermore, the solder in this portion is attached only to a very small portion of the very tip of the tip portion 111, and is configured so as not to hinder bending of the tip portion 111.

The rear end side of the X-ray visible coil 20 (part of the second coarsely wound portion 23) and the tip side of the non-X-ray visible coil 30 (part of the first coarsely wound portion 31) are both soldered to the second tapered portion 113 (described later) of the first core wire 110. The rear end side of the X-ray visible coil 20 and the tip side of the non-X-ray visible coil 30 are connected and integrated by the solder in this portion. Also, in this portion, the respective gaps of the second coarsely wound portion 23 and the first coarsely wound portion 31 are filled with solder. By filling the respective gaps of the second coarsely wound portion 23 and the first coarsely wound portion 31 with solder, the bonding force between the solder and the X-ray visible coil 20 and the non-X-ray visible coil 30 is strengthened, and the X-ray visible coil 20 and the non-X-ray visible coil 30 can be prevented from falling off, thereby improving safety and reliability.

The rear end of the non-X-ray visible coil 30 is located at a position overlapping the first cylindrical portion 116. Therefore, the X-ray visible coil 20 and the non-X-ray visible coil 30 are not extrapolated to the second core wire 120. The rear end of the non-X-ray visible coil 30 (part of the second coarsely wound portion 33) is soldered to the first cylindrical portion 116 to form the fixed portion F. In this portion, the gaps in the second coarsely wound portion 33 are filled with solder. Note that the solder is not shown in Figure 1 etc. By filling the gaps in the second coarsely wound portion 33 with solder, the bonding force between the solder and the non-X-ray visible coil 30 is stronger, preventing the non-X-ray visible coil 30 from falling off and improving safety and reliability. In order to ensure the fixation of the non-X-ray visible coil 30 and the first cylindrical portion 116 in the fixing portion F, the range in which the solder is provided as the fixing portion F is preferably 0.5 mm to 1.5 mm in the axial direction, and more preferably 0.8 mm to 1.2 mm. In addition, in order to facilitate the soldering work, the axial length of the first cylindrical portion 116 is preferably 10 mm to 90 mm, and more preferably 30 mm to 70 mm. In addition, in order to ensure the fixation of the non-X-ray visible coil 30 and the first cylindrical portion 116 and to facilitate the soldering work, the difference between the outer diameter of the first cylindrical portion 116 and the inner diameter of the non-X-ray visible coil 30 is preferably 0.002 mm to 0.018 mm, and more preferably 0.006 mm to 0.014 mm.

By providing the rear end of the non-X-ray visible coil 30 at a position overlapping the first cylindrical portion 116 and fixing this position as the fixing portion F with solder, the fixing operation can be performed more easily and the fixing of the non-X-ray visible coil 30 and the first core wire 110 can be performed more firmly. Fixing at this portion is the most important portion in fixing the non-X-ray visible coil 30 and the first core wire 110, and requires higher reliability than other portions. If an attempt is made to fix the rear end of the non-X-ray visible coil 30 only at the tapered portion, the gap between the tapered portion and the non-X-ray visible coil 30 becomes indefinite, making soldering difficult and causing the strength of the solder to vary, resulting in reduced reliability. In addition, since the first cylindrical portion 116 has a cylindrical shape, it is also easy to manage the gap between the inner diameter of the non-X-ray visible coil 30 and the outer diameter of the first cylindrical portion 116, which stabilizes the strength of the solder and improves reliability. The outer shape (or cross-sectional shape) of the cylindrical portion 116 is not limited to a perfect circle, but may be an ellipse or a slightly distorted circle, as long as it is approximately cylindrical. Note that the above-mentioned positions for soldering the X-ray visible coil 20 and the non-X-ray visible coil 30 are only examples, and if the shape of the core wire is different, they may be fixed at another cylindrical portion, and are not limited to the example of this embodiment.

As shown in Figures 2 and 3, the core wire 10 has a first core wire 110 and a second core wire 120. The total length of the core wire 10 is, for example, about 1,800 to 3,500 mm. The outer diameter of the core wire 10 is, for example, about 0.36 mm at the second cylindrical portion 118 where the outer diameter is maximum.

The first core wire 110 is a linear member that constitutes the tip side (+X side) of the core wire 10. The first core wire 110 is preferably made of a material with excellent flexibility and shape recovery, such as a nickel-titanium (Ni-Ti) alloy, and a nickel-titanium alloy is used in this embodiment. The second core wire 120 is a linear member that constitutes the rear end side (-X side) of the core wire 10. The second core wire 120 is preferably made of a material with high rigidity, such as stainless steel, and stainless steel is used in this embodiment. That is, the core wire 10 is composed of a combination of the first core wire 110 made of a material with a low elastic modulus and the second core wire 120 made of a material with a higher elastic modulus than the material of the first core wire 110.

The elastic modulus of the material forming the first core wire 110 is preferably 30 GPa or more and 100 GPa or less, and the elastic modulus of the material forming the second core wire 120 is preferably 150 GPa or more and 300 GPa or less. The tip side of the guide wire 1 is required to have flexibility to bend along the shape of the thin and complexly curved cerebral blood vessels, so a material with a low elastic modulus as described above is desirable. In particular, in the region where the X-ray visible coil 20 is extrapolated, the core wire 10 needs to be highly flexible. One of the reasons for this is that this region is delivered into the thin and complexly curved cerebral blood vessels. Another reason is that platinum tungsten (Pt-W) alloy, platinum-iridium (Pt-Ir) alloy, etc. used as the material for the X-ray visible coil 20 have higher rigidity than stainless steel, etc. used for the non-X-ray visible coil 30. On the other hand, in order to ensure the overall pushability of the guidewire 1, the second core wire 120 provided at the rear end is made of a material with a higher elasticity than the material used for the first core wire 110.

2 and 3, the rear end (-X side) of the first core wire 110 and the tip end (+X side) of the second core wire 120 are joined at the core joint 50. The first core wire 110 and the second core wire 120 can be joined by, for example, welding. At the tip side of the core wire 10, the outer surface of the range including the extrapolated X-ray visible coil 20 and non-X-ray visible coil 30 (see FIG. 1) is coated with a hydrophilic resin. The range to which this hydrophilic resin coating is applied includes the X-ray visible coil 20 and non-X-ray visible coil 30 as well as parts of the first core wire 110 and second core wire 120 of the core wire 10. By applying a hydrophilic resin coating to the outer surface of the member included in such a range, it is possible to improve the lubricity in the blood vessel. In addition, the hydrophilic resin coating is also applied to the outer surface of the core joint 50, so that it is possible to improve the lubricity of the core joint 50 in the blood vessel.

On the other hand, on the rear end side (-X side) of the core wire 10, the outer surface in the area not coated with hydrophilic resin is coated with a fluororesin. By coating almost the entire outer surface of the rear end side of the core wire 10 with a fluororesin, it is possible to reduce frictional resistance when a catheter (not shown) is inserted onto the guide wire 1.

As shown in Figures 2 and 3, the first core wire 110 has a tip portion 111, a first tapered portion 112, a second tapered portion 113, a third tapered portion 114, a fourth tapered portion 115, a first cylindrical portion 116, a fifth tapered portion 117, and a second cylindrical portion 118 arranged in this order from the tip side (+X side) to the rear end side (-X side). Note that the term "tapered portion" is also used in the following description to collectively refer to the first tapered portion 112, the second tapered portion 113, the third tapered portion 114, the fourth tapered portion 115, and the fifth tapered portion 117. Also, a range in which the taper angle (inclination angle) of the tapered surface that is a part of the shape of a conical surface is constant is treated as one tapered portion and is distinguished from other tapered portions. In other words, the taper angle is different between one tapered portion and another tapered portion.

5 is an enlarged view of range A1 in FIG. 2. FIG. 6 is an enlarged view of range A2 in FIG. 3. FIG. 7 is a view of the core wire 10 in the state of FIG. 3, viewed from the tip side (+X side). The tip portion 111 is provided at the most tip side (+X side) of the first core wire 110, and is formed in a flat plate shape. More specifically, the outer shape of the tip portion 111 as viewed from the direction shown in FIG. 2 and FIG. 5 (direction along the Y axis) and the outer shape as viewed from the direction shown in FIG. 3 and FIG. 6 (direction along the Z axis) are both substantially rectangular and flat. In addition, the tip fixing portion 40 is formed by soldering at the end on the most distal end side of the tip portion 111 (see FIG. 1). Here, the flat shape refers to a flat plate shape, but it is preferable that the tip portion 111 has w111/t≧2 in the shape as viewed from the direction shown in FIG. 7 (or the cross-sectional shape in a cross section perpendicular to the X axis). Here, w111 is the width in the direction (Z-axis direction) perpendicular to the axial direction (X-axis direction) of the tip 111 as viewed from the normal direction of the flat surface 111a of the tip 111, and t is the plate thickness (thickness in the Y direction) of the tip 111. By making w111/t≧2, the direction in which the tip 111 bends during shaping, which will be described later, is unified, and the tip 111 can be prevented from twisting or bending in multiple directions.

Furthermore, the width w111 of the tip portion 111 includes a portion wider than the width w112 of the tip side of the first tapered portion 112 described later. Here, the phrase "includes a wide portion" is used because it is assumed that the width w111 of the tip portion 111 is not constant and the width w111 may change depending on the position in the axial direction (X-axis direction). Since the width w111 of the tip portion 111 includes a portion wider than the width w112 of the tip side of the first tapered portion 112, the tip portion 111 becomes a shape that is sufficiently easier to deform than the first tapered portion 112, making shaping easier. Furthermore, the direction in which the tip portion 111 bends during shaping described later is unified, making it possible to prevent the tip portion 111 from twisting or bending in multiple directions.

Furthermore, as shown in FIG. 7, the shape of the tip 111 viewed from the axial direction (+X direction) is a pair of opposing flat surfaces, and the ends of these flat surfaces are approximately circular, forming an approximately oval shape. That is, the side 111b around the flat surface 111a of the tip 111 is rounded. By having the side 111b of the tip 111 rounded, it is possible to prevent the side 111b from getting caught on the X-ray visible coil 20 when the tip 111 is bent by shaping, and it is possible to easily bend the tip 111 into a desired shape. In this embodiment, the most distal end of the tip 111 is not rounded, but this part may also be rounded. In addition, by having the side 111b of the tip 111 rounded, the tip 111 can be formed by pressing, making it easy to manufacture.

The length L111 of the tip 111 in the axial direction (X-axis direction) is preferably 5 mm or more and 25 mm or less. The reason why the length L111 of the tip 111 is preferably 5 mm or more is that if the length L111 of the tip 111 is less than 5 mm, the region that is easy to bend (highly shapable) is too short and shaping is not possible. The reason why the length L111 of the tip 111 is preferably 25 mm or less is that if the length L111 of the tip 111 exceeds 25 mm, the shapeability is good, but the region with low rigidity is too long, and the forward movement of the guidewire 1 (the property of advancing through a tortuous cerebral blood vessel) is impaired. The length L111 of the tip 111 in the axial direction (X-axis direction) is more preferably 13 mm or more and 19 mm or less.

Furthermore, it is desirable that the width w111 of the tip portion 111 is 0.07 mm or more and 0.18 mm or less. If it is pressed to exceed this width (0.18 mm), the thickness will be too small and the rigidity will be excessively low. On the other hand, if the width is smaller than this width (0.07 mm), the area of the flat plate will be small and it will be difficult to shape. Furthermore, it is desirable that the thickness t of the tip portion 111 is 0.025 mm or more and 0.045 mm or less. If it is pressed to be thinner than this thickness (0.025 mm), the thickness will be too thin and the rigidity will be excessively low. On the other hand, if the thickness is thicker than this thickness (0.045 mm), it will be difficult to shape. Furthermore, it is even more desirable that the width w111 of the tip portion 111 is 0.10 mm or more and 0.15 mm or less.

The first taper section 112, the second taper section 113, the third taper section 114, and the fourth taper section 115 are tapered sections provided to appropriately adjust the rigidity of the tip side (+X side) of the first core wire 110. The configurations of the first taper section 112 to the fourth taper section 115 will be described later.

The first cylindrical section 116 is provided on the rear end side (-X side) of the fourth tapered section 115, and is a cylindrical section with the same diameter as the maximum diameter of the rear end side of the fourth tapered section 115. The fifth tapered section 117 is a tapered section provided on the rear end side (-X side) of the first cylindrical section 116. The second cylindrical section 118 is provided on the rear end side of the fifth tapered section 117, and is a cylindrical section with the same diameter as the maximum diameter of the rear end side of the fifth tapered section 117. As described above, the rear end side end of the second cylindrical section 118 and the tip end side (+X side) of the second core wire 120 are joined at the core joint section 50.

2 and 3, the first taper section 112 to the fourth taper section 115 are four consecutive taper sections that have an increasing outer diameter from the axial tip side (+X side) of the first core wire 110. The axial length from the most axial end (end of tip 111) of the first core wire 110 to the rear end of the fourth taper section 115 (the axial length of the range in which the first taper section 112 to the fourth taper section 115 are provided) is preferably 400 mm or less. Furthermore, it is even more preferable that the axial length from the most axial end (end of tip 111) of the first core wire 110 to the rear end of the fourth taper section 115 (the axial length of the range in which the first taper section 112 to the fourth taper section 115 are provided) is 200 mm or more and 300 mm or less.

The first tapered portion 112 is connected to the tip portion 111 at the rear end side (-X side) of the tip portion 111, and has an approximately conical surface with an outer diameter that increases from the tip side (+X side) to the rear end side (-X side). Here, the first tapered portion 112 has a shape that has a part of an "approximately conical surface" and does not have to be a complete conical surface. The first tapered portion 112 is formed by cutting processing, etc., but when the tip portion 111 is formed by pressing processing, etc. after the first tapered portion 112 is formed, the first tapered portion 112 may be slightly deformed. In such a case, the cross section perpendicular to the axial direction of the tip side (+X side) of the first tapered portion 112 becomes an ellipse shape, a crushed circle shape, etc.

It is desirable that the length L112 of the first taper portion 112 in the axial direction (X-axis direction) is 25 mm or less. It is even more desirable that the length L112 is 7 mm or more and 23 mm or less. If the length L112 is less than 7 mm, the highly flexible region is too short, and the rigidity of the guidewire 1 is high, which may result in poor shaping or an increased risk of damaging blood vessels. If the length L112 exceeds 25 mm, the taper angle described below becomes small, so that the highly flexible region is not effectively formed, the rigidity of the guidewire 1 increases, and the length L111 of the tip portion 111 cannot be set to an appropriate length, making shaping difficult. Here, the reason why the length L111 of the tip portion 111 cannot be set to an appropriate length is that there is a desirable length in the range between the tip portion 111 and the first taper portion 112 as a region that is particularly flexible on the tip side of the guidewire 1. The length in this range, i.e., the combined length of lengths L111 and L112, is preferably 15 mm or more and 35 mm or less, and more preferably 20 mm or more and 30 mm or less. In order to improve flexibility, the ratio of lengths L111 to L112, i.e., L112/L111, is preferably 0.2 or more and 1.0 or less. Furthermore, it is even more preferable that L112/L111 is 0.4 or more and 0.8 or less.

The taper angle θ112 of the first taper portion 112 is preferably 0.05° or more and 0.25° or less in order to provide appropriate flexibility for the first taper portion 112. It is more preferable that the taper angle θ112 is 0.1° or more and 0.2° or less. It is also preferable that the width (≒ outer diameter) w112 of the tip portion (end portion on the +X side) of the first taper portion 112 is 0.04mm or more and 0.12mm or less, and the width (= outer diameter) w113 of the tip portion (end portion on the +X side) of the second taper portion 113 is 0.09mm or more and 0.17mm or less. It is more preferable that the width w112 is 0.06mm or more and 1.00mm or less, and the width w113 is 0.11mm or more and 0.15mm or less. The preferable ranges of the width w112 and the width w113 are also for providing appropriate flexibility for the first taper portion 112.

The outer diameters of the first taper section 112 to the fourth taper section 115 are configured to increase in order from the tip side (+X side) to the rear end side (-X side) of the first core wire 110. In other words, the taper angles of the first taper section 112 to the fourth taper section 115 are set to an angle that inclines so that the outer diameter increases from the tip side to the rear end side of the first core wire 110.

In the first taper section 112 to the fourth taper section 115, the taper angles θ112 to θ115 are set to decrease in order from the tip side (+X side) to the rear end side (-X side) of the first core wire 110. That is, the taper angles θ112 to θ115 have a relationship (order) of θ112>θ113>θ114>θ115. Specifically, the taper angle θ1 of the first taper section 112, which is the most distal end side, is set to 0.05° or more and 0.25° or less, as described above. The taper angles θ113 to θ115 of the second taper section 113 to the fourth taper section 115 are set to be 0.1 to 0.2° or 60 to 98% smaller than the taper angle θ112 of the first taper section 112. By setting it in this way, as shown in Figures 2 and 3, the boundaries between the first taper section 112 to the fourth taper section 115 have a mountain shape when viewed from a direction perpendicular to the X-axis direction. Also, as described above, the taper angle θ112 is particularly large compared to θ113 to θ115. This results in greater stress concentration in the first taper section 112 compared to the second taper section 113 to the fourth taper section 115, making it more likely to deform.

The axial lengths L112 to L115 of the first taper section 112 to the fourth taper section 115 are set to increase in order from the tip side (+X side) to the rear end side (-X side) of the first core wire 110. That is, the tapered section lengths L112 to L115 have a relationship of L112<L113<L114<L115. Specifically, the axial length L112 of the tip-most first taper section 112 is desirably set to 25 mm or less as described above, and more desirably set to 7 mm or more and 23 mm or less. The axial lengths L113 to L114 of the second taper section 113 to the fourth taper section 115 are set to be 15 to 150 mm or 200 to 1700% longer than the axial length L1 of the first taper section 112. For example, if L112 = 15 mm, examples of L113 = 30 mm, L114 = 50 mm, and L115 = 150 mm can be exemplified.

By providing multiple tapered sections as in this embodiment, there is an abrupt change in shape at the boundary between adjacent tapered sections, which causes stress concentration when bending, making the guidewire 1 easier to bend.

8 is a diagram showing the positional relationship between the X-ray visible coil 20 and the non-X-ray visible coil 30 and the core wire 10, with the X-ray visible coil 20 and the non-X-ray visible coil 30 partially not shown. In order to facilitate bending in a curved blood vessel, it is desirable to provide two or more (multiple) taper sections in the range in which the X-ray visible coil 20 is provided. Here, providing two or more (multiple) taper sections in the range in which the X-ray visible coil 20 is provided includes a form in which all of the two taper sections are completely within the range in which the X-ray visible coil 20 is provided, as well as a form in which each part of the two taper sections is within the range in which the X-ray visible coil 20 is provided. In other words, it is desirable that at least one of the boundaries at which the two or more taper sections are connected is within the range in which the X-ray visible coil 20 is provided. As described above, the material forming the X-ray visible coil 20 has higher rigidity than the material used for the non-X-ray visible coil 30, so in this range, it is particularly desirable to increase the flexibility of the core wire 10. In this embodiment, the X-ray visible coil 20 is disposed so as to cover a portion of the first tapered portion 112 and the second tapered portion 113.

By providing multiple taper sections in the area covered by the X-ray visible coil 20, multiple areas with varying outer diameters are arranged, and stress concentration occurs at these positions, making it easier to bend. In addition, the first core wire 110 has a lower elastic modulus than the second core wire 120, making it even easier to bend. Due to these synergistic effects, the first core wire 110 in the area covered by the X-ray visible coil 20 is highly flexible and easy to bend. Therefore, even in the area of the X-ray visible coil 20 where the elastic modulus is higher than that of the non-X-ray visible coil 30, the guide wire 1 is highly flexible and has good blood vessel tracking properties. And because the flexibility is high in the area of the X-ray visible coil 20, the area of the X-ray visible coil 20 can be made longer, making it possible to provide the X-ray visible coil 20 over a long area of 30 mm or more.

Furthermore, it is desirable to provide a continuous tapered section of four or more stages on the rear end side of the tip portion 111, so that the flexibility of the core wire 10 is gradually increased toward the tip side. This is because the tip side is delivered to a more peripheral part of the blood vessel, and therefore requires higher flexibility. Moreover, it is desirable that all of these tapered sections of four or more stages are extrapolated by coils (X-ray visible coil 20 and non-X-ray visible coil 30). By providing a tapered section on the core wire 10, the flexibility of the core wire 10 is increased, and it can be easily bent, but on the other hand, the risk of buckling (kinking) and breaking increases. By extrapolating a coil-shaped member onto the tapered section, it is possible to effectively suppress buckling while maintaining the flexibility in these ranges. In this embodiment, the first tapered section 112 to the fourth tapered section 115, including the tip portion 111, are all extrapolated by the X-ray visible coil 20 or the non-X-ray visible coil 30. Within the range where the non-X-ray visible coil 30 is extrapolated, the first core wire 110 has a part of the second taper section 113, the outer diameter of which increases from the tip side to the rear end side, a third taper section 114, a fourth taper section 115, and a first cylindrical section 116. That is, the non-X-ray visible coil 30 extrapolates a part of the second taper section 113, the third taper section 114, the fourth taper section 115, and a part of the first cylindrical section 116.

In the guidewire 1 of this embodiment, the first taper section 112 to the fourth taper section 115 are formed from the tip of the first core wire 110 in the axial direction (X-axis direction) as shown in Figures 2 and 3. According to this configuration, in the region of the first taper section 112 to the fourth taper section 115, the rigidity of each taper section changes gradually from the rear end side (-X side) of the first core wire 110 to the tip side (+X side). Therefore, the stress acting on the first core wire 110 can be more evenly distributed in the axial direction. Therefore, when the guidewire 1 is rotated or pushed in the axial direction, it is possible to suppress the concentration of stress at a specific point of the first core wire 110. In addition, even if resistance occurs due to friction or the like in the blood vessel when the guidewire 1 is pushed in the axial direction in a curved blood vessel, the bending of any boundary section does not become extremely large, and stress does not concentrate at one boundary section. In this way, in the guidewire 1 of this embodiment, stress does not concentrate at one boundary, so force is more easily transmitted to the tip side (+X side).

Next, a method of using the guidewire 1 of this embodiment will be described, focusing mainly on shaping. Figure 9 is a diagram illustrating an example of a method of shaping the tip side of the guidewire 1 of this embodiment. The tip side of the guidewire 1 can be shaped using a mandrel M. The mandrel M is a cylindrical tool with a rigidity sufficiently higher than that of the guidewire 1. The guidewire 1 is pressed against the pad of a finger by the mandrel M, and the tip portion 111 is bent and fixed. The tip portion 111 and the first tapered portion 112 can be primarily bent by performing the operation of advancing the cylindrical mandrel multiple times. At this time, the strength of the force with which the mandrel M presses the guidewire 1 and the number of times the mandrel M is advanced can be adjusted to bend (shape) the tip side of the guidewire 1 into a desired shape.

In this embodiment, the guidewire 1 has a tip 111 formed in a flat plate shape. Also, the width w111 in the direction perpendicular to the axial direction of the tip 111 as viewed from the normal direction of the flat surface 111a of the tip 111 includes a portion that is wider than the width w112 at the tip side of the first tapered portion 112. As a result, the bending direction of the tip 111 will be the bending direction of the flat surface 111a of the tip 111 without any special operation. Therefore, even if the above-mentioned shaping is performed multiple times, the guidewire 1 will always be bent in the same direction unless the guidewire 1 is intentionally rotated 180°, which prevents the bending direction from becoming twisted and makes it easier to shape into the desired shape. In addition, the axial length of the first taper portion 112 is 25 mm or less, and the taper angle is 0.05° or more and 0.25° or less, so that the flexibility from the first taper portion 112 to the tip side, including the first taper portion 112, is higher than the flexibility from the first taper portion 112 to the rear end side. Therefore, flexibility that can follow the bending of the blood vessel is exhibited. Furthermore, since the side portion 111b around the flat surface 111a of the tip portion 111 has a rounded shape, the side portion 111b is prevented from being caught by the X-ray visible coil 20 during shaping, and it is possible to prevent it from becoming an obstacle to shaping. In addition, since the axial length of the tip portion 111 is 5 mm or more and 25 mm or less, shaping can be easily performed by manual work.

FIG. 10 is a diagram illustrating a method for advancing the guidewire 1 in a cerebral blood vessel. The example shown in FIG. 10 illustrates a case in which the guidewire 1, which has advanced through blood vessel B1, is to be advanced into blood vessel B2, which branches in the opposite direction. Even in such a case, the tip of the guidewire 1 can be directed toward blood vessel B2 by appropriately bending (shaping) the tip as shown in FIG. 10. The direction of the tip of the tip portion 111 bent by shaping can be changed by rotating the guidewire 1 around its axis. Then, with the tip of the tip portion 111 oriented in the direction shown in FIG. 10, the guidewire 1 can be delivered into blood vessel B2 by pushing the guidewire 1 further toward the tip side.

As described above, shaping is performed to select blood vessels at branching points during operation within blood vessels. In order to perform shaping by wrapping around mandrel M, shaping is difficult unless the flat plate is relatively long. On the other hand, if the flat plate is too long, the flexible portion becomes too long and forward movement is impaired. In this embodiment, a certain range of the tip (5 mm to 25 mm) of tip portion 111 is configured as a flat plate, so that it can be easily shaped into a bend with a small radius of curvature and can also exhibit forward movement.

In addition, when the tip 111, which is shaped to correspond to the shape of a branching part of a blood vessel, is advanced, the adjacent part at the rear end side of the tip 111 often comes into contact with the blood vessel. If the rigidity of the part that comes into contact with the blood vessel is high, the blood vessel may be burdened and damaged. In this embodiment, the first taper part 112 is provided in a predetermined range on the rear end side of the tip 111, and the rigidity is reduced by suddenly reducing the diameter, so that the part that comes into contact with the blood vessel can be made flexible and safe. And, since the length L112 of the first taper part 112 is set to, for example, 25 mm or less, which is shorter than the conventional length, the range longer than necessary does not become flexible, and the diameter on the proximal side can be made thicker, realizing good pushability. In this way, the guide wire 1 of this embodiment can achieve both good shapeability and pushability.

Next, an imaging method for imaging the guidewire 1 when the guidewire 1 is delivered to a target position in a blood vessel will be described. The guidewire 1 is delivered into a blood vessel while imaging the X-ray visible coil 20 under X-ray observation. FIGS. 11 and 12 are diagrams showing an example of imaging the guidewire 1. In FIGS. 11 and 12, the non-X-ray visible coil 30 is shown with a dashed line for ease of understanding, but it is the X-ray visible coil 20 that can actually be observed under X-ray observation. As an imaging method for the guidewire 1 of this embodiment, for example, an imaging method including the steps of performing imaging as described below can be exemplified. Note that each imaging step exemplified below is preferably performed in a form in which the operation performed continuously while irradiating X-rays is always imaged as a moving image. The expression "step" is not limited to stopping once or imaging only still images, but is an expression for explaining one process of the moving images that are continuously imaged. Note that although imaging of a moving image is assumed here, imaging of a still image may also be performed. First, a step of imaging the X-ray visible coil 20 inserted into the blood vessel is performed, and for example, an image (including a moving image) as shown in FIG. 11 is captured. This imaging allows the state of the tip of the guide wire 1 to be accurately grasped. Based on the imaging result, it is determined whether the state of the tip of the guide wire 1 is appropriate for the subsequent advancement of the guide wire 1, and if necessary, the practitioner operates the second core wire 120 at hand to move the position of the X-ray visible coil 20 or rotate the direction of the X-ray visible coil 20 while checking the imaged state of the X-ray visible coil 20. Then, a step of imaging the result of the operation of moving the position of the X-ray visible coil 20 or rotating the direction of the X-ray visible coil 20 is performed, and for example, an image (including a moving image) as shown in FIG. 12 is captured.

As described above, the guide wire 1 of this embodiment has a flat tip 111, and the axial length of the tip 111 is 5 mm or more and 25 mm or less, so that it can be easily shaped. In addition, the rear end of the tip 111 has four consecutive taper sections (first taper section 112, second taper section 113, third taper section 114, and fourth taper section 115), and the rigidity changes gradually, so that the stress acting in the axial direction of the core wire can be more evenly distributed. In addition, since the four consecutive taper sections are provided, it is possible to suppress the concentration of stress at a specific point of the core wire 10 when the guide wire 1 is rotated or pushed in the axial direction. Furthermore, since all of the four consecutive taper sections are extrapolated with a coil, buckling can be effectively suppressed while maintaining the flexibility of these ranges, and as a result, pushability can be improved. As mentioned above, the guidewire 1 of this embodiment has the characteristic of being easily shapable, but shaping is not essential.

(Modifications)
The present disclosure is not limited to the above-described embodiment, and various modifications and variations are possible, and these are also within the scope of the present disclosure.

(1) In the embodiment, four tapered sections (111-114) are provided continuously from the tip side (+X side) to the rear end side (-X side) of the first core wire 110, and these are extrapolated with a coil-shaped member. The number of tapered sections to be extrapolated with a coil is not limited to four, and may be five or more. Also, a cylindrical portion may be provided between the tapered sections.

(2) In the embodiment, an example has been described in which the first core wire 110 is made of a nickel-titanium alloy and the second core wire 120 is made of stainless steel. This is not limited to the above, and for example, the entire core wire 10 may be made of a nickel-titanium alloy or stainless steel. That is, the core wire 10 may be made of both the nickel-titanium alloy and stainless steel as in the embodiment, or may be made of either the nickel-titanium alloy or stainless steel.

(3) In the embodiment, the shapes, structures, arrangements, etc. of the exemplified X-ray visible coil 20, non-X-ray visible coil 30, and tip fixing portion 40 can be selected as appropriate and are not limited to the example embodiments.

(4) In the embodiment, an example was given in which a hydrophilic resin coating was applied to the outer surface of a member included in a predetermined range of the core wire 10. However, this is not limited to the above, and for example, the outer surface of the member may not be coated with a hydrophilic resin.

(5) In the embodiment, an example has been described in which a fluororesin coating is applied to a predetermined area of the outer surface of the core wire 10. This is not limiting, and for example, a configuration may be adopted in which no fluororesin coating is applied, or in the embodiment, a hydrophilic resin coating may be applied to the area where the fluororesin coating is applied.

(6) The hydrophilic resin coating and fluororesin coating exemplified in the embodiment both have the effect of reducing frictional resistance, and therefore may be applied to any part of the core wire 10. The embodiment illustrates a preferred use form of the hydrophilic resin coating and the fluororesin coating. In this way, the guide wire 1 of the embodiment may be applied with only one of the hydrophilic resin coating and the fluororesin coating.

The embodiments and variations can be used in any suitable combination, but detailed explanations will be omitted. Furthermore, the present disclosure is not limited to the embodiments described above.

1 Guide wire 10 Core wire 20 X-ray visible coil 21 First loosely wound section 22 Densely wound section 23 Second loosely wound section 30 Non-X-ray visible coil 31 First loosely wound section 32 Densely wound section 33 Second loosely wound section 40 Tip fixing section 50 Core joint section 110 First core wire 111 Tip section 111a Flat surface 111b Side section 112 First tapered section 113 Second tapered section 114 Third tapered section 115 Fourth tapered section 116 First cylindrical section 117 Fifth tapered section 118 Second cylindrical section 120 Second core wire

Claims (4)

A core wire extending from the rear end to the front end;
A tip portion provided at a tip of the core wire and formed in a flat plate shape;
a tapered portion connected to a rear end of the tip portion and having four or more continuous steps whose outer diameter increases from the tip side to the rear end side;
A coil is inserted around all of the tapered portions provided in four or more consecutive stages and the tip portion;
a fixing portion that fixes the rear end of the coil and the core wire;
Equipped with
A blood vessel guidewire, wherein the length of the tip portion in the axial direction is 5 mm or more and 25 mm or less. The vascular guidewire according to claim 1,
The fixed portion is connected to a rear end of the tapered portion provided in four or more successive steps and is provided on a cylindrical portion formed into a cylindrical shape. The blood vessel guidewire according to claim 1 or 2,
The coil includes an X-ray visible coil inserted at least in the tip portion,
a non-X-ray visible coil connected to a rear end of the X-ray visible coil;
A vascular guidewire comprising: The blood vessel guidewire according to claim 1 or 2,
A vascular guidewire for use in the carotid artery or cerebral blood vessels.

Images