JP7764150B2 - Multilayer coil body - Google Patents

Description

The present invention relates to a multilayer coil body.

Elongated medical instruments such as catheters are known as instruments inserted into body cavities such as blood vessels to treat lesions. When rotating the tip of such medical instruments inserted into a body cavity, excellent torque transmission is required to ensure that the rotational force at the handle is reliably transmitted to the tip.

As an example of the above-mentioned medical device, one that has a coil body with multiple coil layers arranged adjacent to each other in a direction (radial direction) perpendicular to the longitudinal axis of the medical device has been disclosed (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2019-107326

However, while the coil bodies used in the above-mentioned conventional medical devices can ensure sufficient torque transmission, they are not necessarily sufficient in terms of ensuring high flexibility to follow the complex curves of the body cavity.

The present invention was made based on the above circumstances, and its purpose is to provide a multi-layer coil body that can achieve both sufficient torque transmission and high flexibility.

Some aspects of the present disclosure include:
(1) a hollow first coil layer in which a first winding is wound spirally;
a third coil layer provided to cover the first coil layer and having a third winding wound in a spiral shape;
a second coil layer provided between the first coil layer and the third coil layer so as to be adjacent thereto, the second coil layer having a second winding wound in a spiral shape,
a cross-sectional area of at least one winding constituting the second coil layer is larger than a cross-sectional area of at least one winding constituting the first coil layer and the third coil layer;
a multilayer coil body, characterized in that a gap is formed between at least some of the second windings adjacent to each other in the longitudinal direction;
(2) The multilayer coil body according to (1), wherein the outermost periphery of the second winding has a substantially rectangular cross-sectional contour.
(3) The multilayer coil body according to (1) or (2), wherein the gaps formed between the second windings include two or more gaps having different lengths in the major axis direction.
(4) A multilayer coil body according to (3) above, in which the second winding contains a radiopaque material, and (5) a multilayer coil body according to any one of (1) to (4) above, in which a conductor is provided in the gap formed between the second windings.

In this specification, the term "winding" refers to a linear member that is wound spirally to form a coil layer. The member may be a solid wire (single wire) or a twisted wire. The "transverse area of a winding" refers to the cross-sectional area of the winding in a cross section perpendicular to the spiral direction. In other words, it can also be referred to as the cross-sectional area of the winding in a cross section perpendicular to the direction of progression (spiral direction) of the winding that progresses spirally.

The present invention can provide a multi-layer coil body that combines sufficient torque transmission and high flexibility.

1 is a schematic longitudinal sectional view showing the entire first embodiment. FIG. 1 is a schematic vertical cross-sectional view showing a part of a first embodiment. FIG. 10 is a schematic vertical cross-sectional view showing a part of a modified example. FIG. 10 is a schematic longitudinal sectional view showing a part of a second embodiment. FIG. 10 is a schematic longitudinal sectional view showing a part of a third embodiment. FIG. 10 is a schematic vertical cross-sectional view showing the entire fourth embodiment. FIG. 10 is a schematic longitudinal sectional view showing the entire fifth embodiment. FIG. 10 is a schematic vertical cross-sectional view showing the entire sixth embodiment. FIG. 13 is a schematic longitudinal sectional view showing a part of a sixth embodiment. FIG. 10 is a schematic vertical cross-sectional view showing a part of a modified example.

The multilayer coil body disclosed herein comprises a hollow first coil layer around which a first winding is spirally wound; a third coil layer that is disposed so as to cover the first coil layer and has a third winding wound around it; and a second coil layer that is disposed adjacent to and between the first coil layer and the third coil layer and has a second winding wound around it; wherein the cross-sectional area of at least one winding constituting the second coil layer is larger than the cross-sectional area of at least one winding constituting the first coil layer and the third coil layer, and a gap is formed between at least some of the adjacent second windings in the longitudinal direction.

In this specification, "distal side" refers to the direction along the longitudinal axis of the multilayer coil body, advancing toward the treatment site. "Proximal side" refers to the direction along the longitudinal axis, opposite the distal side. Furthermore, "distal" refers to the distal end of any component or part, and "proximal end" refers to the proximal end of any component or part. Unless otherwise specified, "longitudinal direction" and "radial direction" refer to the longitudinal axis direction and radial direction (direction perpendicular to the longitudinal axis direction) of the multilayer coil body, respectively.

The following describes first to sixth embodiments of the present invention with reference to the drawings, but the present invention is not limited to the embodiments shown in the drawings. Furthermore, the dimensions shown in each drawing are intended to facilitate understanding of the implementation, and do not necessarily correspond to actual dimensions. In each drawing, the left side of the drawing indicates the distal end of the multilayer coil body, and the right side indicates the proximal end of the multilayer coil body.

[First embodiment]
1 and 2 are schematic diagrams showing a first embodiment. As shown in FIGS. 1 and 2, a multilayer coil body 1 is generally composed of a first coil layer 11, a second coil layer 21, and a third coil layer 31.

The first coil layer 11 is a hollow layer around which the first winding wire 11w is wound in a spiral shape. Specifically, the first coil layer 11 can be formed, for example, by using a single wire (single wire) or twisted wire with a circular cross section as the first winding wire 11w and winding this member in a single or multiple strand configuration. Adjacent first winding wires 11w in the longitudinal direction may be in contact with each other or spaced apart. When the first winding wires 11w are spaced apart, the gap between the first winding wires 11w may be configured to be smaller than the gap between the second winding wires 21w (described below) (not shown). In this embodiment, a single wire 111w with a circular cross section is used as the first winding wire 11w, and this first winding wire 11w is wound in a single strand configuration and arranged so that adjacent first winding wires 11w are in contact with each other. Furthermore, an inner cavity 1h is formed inside the first coil layer 11. For example, a guidewire (not shown) can be inserted into the lumen 1h.

The second coil layer 21 is located adjacent to the first coil layer 11 and the third coil layer 31 (described later), and is a layer in which the second winding 21w is wound in a spiral shape. Specifically, the second coil layer 21 can be formed, for example, by using a solid wire (single wire) or a twisted wire as the second winding 21w and winding this member in a single or multiple strand configuration.

The outermost peripheral contour shape in cross section of the second winding 21w may be circular or approximately rectangular. If the contour shape is rectangular, the cross-sectional area of the second winding 21w can be increased while saving space, and a second winding with a rectangular cross section can effectively improve torque transmission. In this embodiment, a single wire 211w whose outermost peripheral contour shape in cross section is rectangular is used as the second winding 21w, and the second coil layer 21 is exemplified by a single-strand winding of this second winding 21w.

When the cross-sectional contour of the second winding 21w is rectangular, the aspect ratio of the cross-section (the ratio of width to length of the rectangle) may be set, for example, between 1:10 (flat shape) and 1:1 (square shape). In the case of a flat shape, it is preferable to position the flat surfaces so that they are in contact with the first and third coil layers 11, 31. This prevents the multilayer coil body 1 from collapsing due to pressure from the outside in the radial direction, and further improves torque transmissibility and flexibility, particularly torque transmissibility. Furthermore, a square shape can further improve torque transmissibility and flexibility, particularly flexibility.

The third coil layer 31 is provided to cover the first coil layer 11 and is a layer in which the third winding 31w is wound in a spiral shape. Specifically, the third coil layer 31 can be formed, for example, by using a solid wire (single wire) or twisted wire with a circular cross section as the third winding 31w and winding this member in a single or multiple strand configuration. Adjacent third windings 31w in the longitudinal direction may be in contact with each other or spaced apart. When the third windings are spaced apart, as shown in FIG. 3, the gap A31g between the third windings A31w may be configured to be smaller than the gap 21g between the second windings 21w, for example. In this embodiment, a single wire 311w with a circular cross section is used as the third winding 31w, and the third coil layer 31 is formed by winding this third winding 31w as a single strand and forming adjacent third windings 31w in contact with each other (see Figure 2).

Here, gaps 21g are formed between at least some of the adjacent second windings 21w in the longitudinal direction. These gaps 21g may be formed between each of the adjacent second windings, or may be formed only between specific second windings, with the second windings other than the specific second windings being in contact with each other.

The length L of the gap 21g in the longitudinal direction can be determined as appropriate depending on the flexibility required for each portion of the multilayer coil body 1 in the longitudinal direction. The length L of the gap 21g can be set to, for example, 0.001 mm to 1 mm. If the length L of the gap 21g is large, the flexibility of the multilayer coil body in that portion can be increased, and if the length L of the gap 21g is small, the rigidity of the multilayer coil body in that portion can be increased. This embodiment illustrates a multilayer coil body 1 in which second windings 21w with gaps 21g of the same length L are adjacent to each other.

Furthermore, in the multilayer coil body 1, the cross-sectional area of at least one winding 21w constituting the second coil layer 21 is configured to be larger than the cross-sectional area of at least one winding 11w, 31w constituting the first coil layer 11 and the third coil layer 31. More specifically, the cross-sectional area of at least one winding 21w constituting the second coil layer 21 is configured to be larger than the cross-sectional area of the winding having the largest cross-sectional area among the windings 11w, 31w constituting the first coil layer 11 and the third coil layer 31.

In the multilayer coil body 1 of this embodiment, the first winding 11w and the third winding 31w are each composed of a single wire and a single strand, and the second winding 21w is also composed of a single wire and a single strand. Therefore, the cross-sectional area of the single wire 211w (strand) constituting the second winding 21w is larger than both the cross-sectional area of the single wire 111w (strand) constituting the first winding 11w and the cross-sectional area of the single wire 311w (strand) constituting the third winding 31w.

The winding directions of adjacent windings in the radial direction may be opposite to each other (for example, the first winding is S-twisted, the second winding is Z-twisted, and the third winding is S-twisted). When the winding directions are opposite to each other in this way, the force in the longitudinal direction applied to adjacent windings in the radial direction can be made to face each other when the multilayer coil body is rotated around the longitudinal axis. This makes it possible to suppress a decrease in torque transmission caused by the separation between adjacent windings in the longitudinal direction, regardless of the direction in which the multilayer coil body is rotated.

The wire material constituting the first winding 11w, second winding 21w, and third winding 31w can be, for example, stainless steel such as SUS316; superelastic alloys such as Ni-Ti alloys; or radiopaque metals such as platinum and tungsten, from the perspective of providing antithrombogenicity and biocompatibility. The wire material for each winding may be the same material, or may contain different materials.

As described above, the multilayer coil body 1 has the above-described configuration, which allows it to achieve both sufficient torque transmission and high flexibility. Furthermore, by appropriately adjusting the length L (spacing) of the gap 21g, the multilayer coil body 1 can be made either hard or soft, allowing the balance between flexibility and rigidity to be adjusted appropriately.

Second Embodiment
4 is a schematic diagram showing the second embodiment. As shown in FIG. 4, the multilayer coil body 2 is generally composed of a first coil layer 11, a second coil layer 22, and a third coil layer 31. The multilayer coil body 2 differs from the first embodiment in that it includes the second coil layer 22. Note that the first coil layer 11 and the third coil layer 31 are the same as those in the first embodiment, and therefore the same parts are denoted by the same reference numerals and detailed description thereof will be omitted. Furthermore, the configuration other than the configuration of the second coil layer 22 described below is the same as that of the first embodiment.

The second coil layer 22 is disposed adjacent to the first coil layer 11 and the third coil layer 31, and is a layer in which the second winding 22w is wound in a spiral shape. In this embodiment, the second winding 22w is made of three single wires 221w, 222w, and 223w whose outermost periphery has a rectangular cross-sectional outline and whose cross-sectional areas are equal to each other, and the second coil layer 22 is exemplified by a triple-strand (multi-strand) winding.

In the multilayer coil body 2, a gap is formed between adjacent second windings 22w in the longitudinal direction of the second coil layer 22. Specifically, in the multilayer coil body 2, three single wires 221w, 222w, and 223w that make up the second winding 22w are in contact with each other in the longitudinal direction, forming a set, and a gap 22g is formed between adjacent sets of windings (three second windings 22w) in the longitudinal direction.

In the multilayer coil body 2 of this embodiment, the first winding 11w and the third winding 31w are each composed of a single wire and a single strand, and the second winding 22w is composed of a single wire and a triple (multi-strand) strand. Specifically, the cross-sectional area of at least one winding 21w constituting the second coil layer 21 is configured to be larger than the cross-sectional area of at least one winding 11w, 31w constituting the first coil layer 11 and the third coil layer 31. More specifically, the cross-sectional area of at least one winding 21w constituting the second coil layer 21 is configured to be larger than the cross-sectional area of the winding with the largest cross-sectional area among the windings 11w, 31w constituting the first coil layer 11 and the third coil layer 31.

As described above, the multilayer coil body 2 has the above-described configuration, which allows it to achieve both sufficient torque transmission and high flexibility. Furthermore, by appropriately adjusting the length L (spacing) of the gap 22g, the multilayer coil body 2 can be made either hard or soft, allowing the balance between flexibility and rigidity to be adjusted appropriately.

[Third embodiment]
5 is a schematic longitudinal sectional view showing the third embodiment. As shown in FIG. 5, the multilayer coil body 3 is generally composed of a first coil layer 11, a second coil layer 23, and a third coil layer 31. The multilayer coil body 3 differs from the first embodiment in that it includes the second coil layer 23. Note that the first coil layer 11 and the third coil layer 31 are the same as those in the first embodiment, and therefore the same parts are denoted by the same reference numerals and detailed description thereof will be omitted. Furthermore, the configuration other than the configuration of the second coil layer 23 described below is the same as that of the first embodiment.

The second coil layer 23 is disposed adjacent to the first coil layer 11 and the third coil layer 31, and is a layer in which the second winding 23w is wound in a spiral shape. In this embodiment, the second winding 23w is a single wire 231w whose outermost periphery has a rectangular outline in cross section, and the second coil layer 23 is exemplified by a single-strand (single-strand) winding of this wire.

In the multilayer coil body 3, gaps 23g are formed between adjacent second windings 23w in the longitudinal direction of the second coil layer 23. The gaps 23g formed between the second windings 23w in the multilayer coil body 3 include two or more gaps 23g with different lengths in the longitudinal direction (e.g., gaps 231g, 232g).

Examples of gaps 23g with different lengths include gaps 23g where the length L of the gap 23g increases monotonically and/or stepwise along the longitudinal direction, and gaps 23g where the length L varies only at a specific portion along the longitudinal direction (where the length L of the gap 23g is larger or smaller only at a specific portion). In this embodiment, the second coil layer 23 is exemplified as having gaps 23g where the length L of the gap 23g increases monotonically toward the tip.

In the multilayer coil body 3, the second winding 23w may contain a radiopaque material (e.g., an X-ray opaque material). If the wire material constituting the second winding 23w contains a radiopaque material, the position of the gap in the longitudinal direction can be identified in a radiographic image based on its relationship to the length L of the contrasted gap and the lengths of other gaps, allowing for more accurate manipulation of the multilayer coil body within a body cavity.

Examples of the radiopaque material include gold, platinum, tungsten, and alloys containing these elements (e.g., platinum-nickel alloys). The radiopaque material may also be a combination of a radiopaque material and a radiotransparent material, such as a material coated on the surface of a non-radiopaque material (radiotransparent material).

As described above, the multilayer coil body 3 includes two or more gaps 23g with different lengths L in the longitudinal direction, which allows the multilayer coil body 3 to vary in flexibility in the longitudinal direction. Furthermore, by appropriately adjusting the length L (spacing) of the gaps 23g, the multilayer coil body 3 can be made either rigid or flexible, allowing the balance between flexibility and rigidity to be adjusted appropriately.

[Fourth embodiment]
6 is a schematic longitudinal cross-sectional view showing a fourth embodiment. In this embodiment, a catheter using the multilayer coil body of the present disclosure is illustrated. As shown in FIG. 6, the catheter C is generally composed of a multilayer coil body 4, a distal tip 44, and a base portion 54.

The multilayer coil body 4 includes a first coil layer 11, a second coil layer 24, and a third coil layer 31. The first coil layer 11 and the third coil layer 31 are the same as those in the first embodiment, so the same parts are given the same reference numerals and detailed descriptions are omitted. Furthermore, the configuration is the same as that of the first embodiment, except for the configuration of the second coil layer 24, which will be described below.

The second coil layer 24 of the catheter C is configured so that the length L of the gap 241g between the second windings 24w at the distal end of the multilayer coil body 4 is greater than the length L of the gap 242g at the proximal end. This makes the distal end of the multilayer coil body 4 more flexible than the proximal end, allowing the catheter C to be advanced more smoothly while the distal end conforms to the curved body cavity.

The distal tip 44 is a component joined to one end of the multilayer coil body 4. Specifically, the distal tip 44 is formed so that its distal end is rounded toward the distal end, for example, to facilitate movement of the multilayer coil body 4 within a body cavity such as a blood vessel. The distal tip 44 has an inner cavity 44h with an opening 44a at its tip.

One method for joining the distal tip 44 to the multilayer coil body 4 is to embed the distal ends of the first winding 11w, second winding 24w, and third winding 31w that make up the multilayer coil body 4 in the base end of the distal tip 44 by welding or other methods.

The material that makes up the distal tip 44 is preferably antithrombotic, biocompatible, and flexible enough to absorb impacts on body cavities, etc. Examples of such materials include resin materials such as polyurethane and polyurethane elastomer.

The base 54 is the component with which the operator grips the catheter C. The base 54 is connected, for example, to the proximal end of the multilayer coil body 4 and has a lumen 54h that communicates with the lumen 4h of the multilayer coil body 4. An opening 54a is formed at the proximal end of the lumen 54h. The shape of the base 54 is not particularly limited as long as it does not impair the effects of the present invention, and can be formed, for example, into a shape that is easy for the operator to manipulate.

Here, the lumen M is formed by the lumen 44h of the distal tip 44, the lumen 4h of the multilayer coil body 4, and the lumen 54h of the base portion 54. A medical device such as a guidewire (not shown) is inserted through this lumen M.

Next, we will explain how to use catheter C. Here, we will explain an example of a procedure in which catheter C is used as a guiding catheter to dilate a stenotic area in a coronary artery of the heart with a balloon catheter.

Prior to using catheter C, first, guidewire A (not shown) is inserted into the blood vessel and its tip is advanced until it approaches the entrance to the coronary artery of the heart. Next, guidewire A is inserted into the lumen M of catheter C, and catheter C is advanced while being pushed into the blood vessel along guidewire A so that the tip reaches the entrance to the coronary artery of the heart. During this process, catheter C is advanced while following the curvature of the blood vessel.

Next, guidewire A is removed and replaced with a thinner guidewire B (not shown) for a balloon catheter, and the tip of guidewire B is brought to a position where it passes through the narrowed area via catheter C. Next, a balloon catheter (not shown) is inserted along guidewire B to the inside of the narrowed area, and the balloon dilates the narrowed area to perform treatment. After this treatment, the balloon catheter, guidewire B, and catheter C are removed from the body in this order to complete the procedure.

As described above, the catheter C has the above-described configuration, and thanks to the excellent torque transmission and high flexibility of the multilayer coil body 4, the rotational force applied to the base portion 54 can be reliably transmitted to the tip portion of the catheter C, and it can also exhibit high tracking ability even within complexly curved blood vessels. Furthermore, by appropriately adjusting the length L (spacing) of the gap 24g, the multilayer coil body 4 can be made either rigid or flexible, allowing the balance between flexibility and penetration force of the catheter C to be appropriately adjusted.

Fifth Embodiment
7 is a schematic longitudinal cross-sectional view showing a fifth embodiment. In this embodiment, a guidewire using the multilayer coil body of the present disclosure is illustrated. As shown in FIG. 7 , the guidewire G1 is generally composed of a core shaft 65, a multilayer coil body 5, a distal fixing portion 75, and a proximal fixing portion 85.

The core shaft 65 is a longitudinal shaft. The core shaft 65 can be configured to have, for example, an enlarged diameter portion 652, a small diameter portion 651, and a large diameter portion 653.

The expanded diameter section 652 is a section whose diameter expands toward the base end. The small diameter section 651 is a section whose base end is located at the tip of the expanded diameter section 652 and extends toward the tip end. The large diameter section 653 is a section whose tip is located at the base end of the expanded diameter section 652 and extends toward the base end. Each of the small diameter section 651 and the large diameter section 653 can be configured to have a constant outer diameter along the longitudinal axis direction of the core shaft 65.

The material for the core shaft 65 can be, for example, stainless steel such as SUS304 or a superelastic alloy such as a Ni-Ti alloy, in order to improve the flexibility of the guidewire G1 and to provide it with antithrombogenic and biocompatible properties.

The multilayer coil body 5 includes a first coil layer 11, a second coil layer 25, and a third coil layer 31. The first coil layer 11 and the third coil layer 31 are the same as those in the first embodiment, so the same parts are denoted by the same reference numerals and detailed descriptions thereof are omitted. Furthermore, the configuration other than that of the second coil layer 25, which will be described below, is the same as that of the first embodiment.

The second coil layer 25 of the guidewire G1 is configured so that the length L of the gap 251g at the distal end of the multilayer coil body 5 is greater than the length L of the gap 252g at the proximal end. This makes the distal end of the multilayer coil body 5 more flexible than the proximal end, allowing the guidewire G1 to advance more smoothly while following the curved body cavity.

The tip fixing portion 75 is a portion that fixes the tip of the multilayer coil body 5 to the tip of the core shaft 65. Specifically, the tip fixing portion 75 can be formed, for example, so that the tip has a generally hemispherical shape that is convexly curved toward the tip. This reduces resistance when the guidewire G1 advances through the blood vessel, allowing for smooth insertion of the guidewire G1.

The tip fixing portion 75 can be formed, for example, by melting the tips of the first winding 11w, second winding 25w, and third winding 31w that make up the core shaft 65 and/or multilayer coil body 5, or by joining the core shaft 65 and multilayer coil body 5 using a brazing material. Examples of brazing materials include metal brazing materials such as Sn-Pb alloy, Pb-Ag alloy, Sn-Ag alloy, and Au-Sn alloy.

The base end fixing portion 85 is a portion that fixes the base end of the multilayer coil body 5 to the core shaft 65. Specifically, the base end fixing portion 85 can be formed, for example, on the expanded diameter portion 652 of the core shaft 5.

The base end fixing portion 85 can be formed, for example, by melting the base ends of the first winding 11w, second winding 25w, and third winding 31w that make up the multilayer coil body 5, or by joining the core shaft 65 and the multilayer coil body 5 using a brazing material. The brazing material can be, for example, the same brazing material as that used to form the tip fixing portion 75.

Note that the guidewire G1 can be used in the same manner as the guidewire A and guidewire B described in the usage of the catheter C of the fourth embodiment, for example.

As described above, the guidewire G1 has the above-described configuration, and thanks to the excellent torque transmission and high flexibility of the multilayer coil body 5, it can reliably transmit rotational force applied to the base end of the core shaft 65 to the distal end of the guidewire G1, and can also demonstrate high tracking ability even within complexly curved blood vessels. Furthermore, by appropriately adjusting the length L (spacing) of the gap 25g, the multilayer coil body 5 can be made either rigid or flexible, allowing the balance between flexibility and penetration force of the guidewire G1 to be appropriately adjusted.

Sixth Embodiment
8 and 9 are schematic longitudinal cross-sectional views showing a sixth embodiment. In this embodiment, a guidewire in which a conductor (lead wire) is arranged using the multilayer coil body of the present disclosure is exemplified. As shown in FIGS. 8 and 9 , the guidewire G2 is generally composed of a core shaft 65, a multilayer coil body 6, a distal fixation portion 75, a proximal fixation portion 85, a sensor 961, a lead wire 962, and a covering member 963. The guidewire G2 differs from the fifth embodiment in that it includes the multilayer coil body 6, the sensor 961, the lead wire 962, and the covering member 963. The core shaft 65, the distal fixation portion 75, and the proximal fixation portion 85 are the same as those in the fifth embodiment, and therefore the same components are designated by the same reference numerals and detailed description thereof will be omitted.

The multilayer coil body 6 includes a first coil layer 11, a second coil layer 25, and a third coil layer 36. The first coil layer 11 and the second coil layer 25 are the same as those in the fifth embodiment, so the same parts are denoted by the same reference numerals and detailed descriptions thereof are omitted. Furthermore, the configuration is the same as that of the fifth embodiment, except for the configuration of the third coil layer 36, which will be described below.

In the third coil layer 36 of the guidewire G2, adjacent third windings 36w are spaced apart in the longitudinal direction. The gaps 36g between the third windings 36w can be configured to be smaller than the gaps 25g between the second windings 25w, for example.

The base end of the sensor 961 is connected to the tip of a lead wire 962 (described below), and is positioned along the spiral gap 25g formed between adjacent second windings 25w. The tip of the sensor 961 can be embedded in the tip fixing portion 75, or positioned so that it abuts or is close to the base end of the tip fixing portion 75, for example.

Examples of sensors 961 include temperature sensors, pressure sensors, etc.

The sensor 961 can be suitably shaped as a wire or ribbon sensor so that it fits into the gap 25g formed between adjacent second windings 25w.

The lead wire 962 is an electrical conductor that electrically connects the sensor 961 to an external measuring device main body (not shown). The tip end portion of the lead wire 962 is provided in the gap 25g formed between the second windings 25w. Specifically, the tip end portion of the lead wire 962 is arranged so as to follow the spiral gap 25g formed between adjacent second windings 25w. The base end portion of the lead wire 962 can, for example, extend linearly along the longitudinal direction on the outer circumferential surface of the core shaft 65.

It is preferable that the outer periphery of the lead wire 962 be located inside the outer periphery of the second winding 25w in the multilayer coil body 6 (in the direction of the central axis of the guide wire G2). This prevents large external forces from being directly applied to the lead wire 962, preventing deformation or damage to the lead wire 962.

The material for the lead wire 962 is preferably a metal different from the material for the first, second, and third windings 11w, 25w, and 36w, and more preferably a metal with lower resistance than the material for the first, second, and third windings 11w, 25w, and 36w. Examples of such materials include gold, silver, copper, and alloys containing these. These materials have lower rigidity and a smaller elastic range than stainless steel such as SUS316 and superelastic alloys such as Ni-Ti alloys that make up the multilayer coil body 6.

The covering member 963 electrically insulates the sensor 961 and lead wire 962 from surrounding components such as the multilayer coil body 6, and from bodily tissues such as blood vessels and blood, and also secures them to the multilayer coil body 6.

Examples of materials that can be used to form the covering member 963 include thermosetting electrically insulating resins such as polyimide and thermoplastic electrically insulating resins such as polyamide. Such resins can be formed, for example, by arranging the sensor 961 and lead wires 962 in the multilayer coil body 6 and core shaft 65, then applying a resin composition for forming the resin to the outer periphery of the sensor 961 and lead wires 962 by dipping, spraying, or the like, and then subjecting them to a heat treatment.

As described above, the guide wire G2 has the above-described configuration, so the lead wire 962, which has lower rigidity and a smaller elastic range than stainless steel such as SUS316 or superelastic alloys such as Ni-Ti alloys, can be reinforced with the multilayer coil body 6, preventing breakage of the lead wire 962. Furthermore, by storing the lead wire 962 in the gap 25g of the second winding 25w, space can be used effectively, preventing the guide wire G2 from becoming bulky.

The present invention is not limited to the configurations of the above-described embodiments, but is intended to include all modifications that are defined by the claims and are equivalent in meaning to and within the scope of the claims. For example, some of the configurations of the above-described embodiments may be deleted or replaced with other configurations, or other configurations may be added to the configurations of the above-described embodiments.

For example, in the above-described embodiment, a multilayer coil body was described in which the second winding is a single wire whose outermost periphery has a rectangular outline in cross section, and the second coil layer is formed by winding this second winding in a single or multiple strand configuration. However, the second coil layer 27 may have a shape other than rectangular, such as a circular single wire 271w, for example (see FIG. 10).

In the above-described embodiment, a multilayer coil body including a second coil layer using a solid wire as the second winding was described. However, the second coil layer may be configured with a winding including a twisted wire as the second winding. In such a case, the cross-sectional shape of the wire (single wire) that constitutes the twisted wire may be rectangular, or may be a shape other than rectangular (such as circular), or may be a mixture of these. Furthermore, the second winding that constitutes the second coil layer may be formed so that the outermost periphery of the wire as a whole has a substantially rectangular outline shape in cross section.

In addition, in the above-described embodiment, a multilayer coil body consisting of three layers (a first coil layer, a second coil layer, and a third coil layer) was described. However, the multilayer coil body may have a second coil layer between the first coil layer and the third coil layer. For example, the multilayer coil body may have a further coil layer inside the first coil layer, or may have a further coil layer outside the third coil layer.

1, 2, 3, 4, 5, 6 Multilayer coil body 11 First coil layer 11w First winding 21, 22, 23, 24, 25, 27 Second coil layer 21w, 22w, 23w, 24w, 25w, 27w Second winding 21g, 22g, 23g, 24, 25g Gap 31, A31, 36 Third coil layer 31w, A31w, 36w Third winding C Catheter G1, G2 Guide wire

Claims (6)

a hollow first coil layer in which a first winding is wound spirally;
a third coil layer provided to cover the first coil layer and having a third winding wound in a spiral shape;
a second coil layer provided between the first coil layer and the third coil layer so as to be adjacent thereto, the second coil layer having a second winding wound in a spiral shape,
a cross-sectional area of at least one winding constituting the second coil layer is larger than a cross-sectional area of at least one winding constituting the first coil layer and the third coil layer;
a gap is formed between at least some of the second windings adjacent to each other in the longitudinal direction;
the second coil layer is adjacent to both the first coil layer and the third coil layer over the entire length in the longitudinal direction ;
The outermost periphery of the second winding has a substantially rectangular cross section.
Multilayer coil body. a hollow first coil layer in which a first winding is wound spirally;
a third coil layer provided to cover the first coil layer and having a third winding wound in a spiral shape;
a second coil layer provided between the first coil layer and the third coil layer so as to be adjacent thereto, the second coil layer having a second winding wound in a spiral shape,
a cross-sectional area of at least one winding constituting the second coil layer is larger than a cross-sectional area of at least one winding constituting the first coil layer and the third coil layer;
a gap is formed between at least some of the second windings adjacent to each other in the longitudinal direction;
the second coil layer is adjacent to both the first coil layer and the third coil layer over the entire length in the longitudinal direction;
The gaps formed between the second windings include two or more gaps having different lengths in the longitudinal direction.
Multilayer coil body. 2. The multilayer coil body according to claim 1 , wherein the gaps formed between the second windings include two or more gaps having different lengths in the major axis direction. 4. The multilayer coil assembly according to claim 2 or 3, wherein the second winding includes a radiopaque material. a hollow first coil layer in which a first winding is wound spirally;
a third coil layer provided to cover the first coil layer and having a third winding wound in a spiral shape;
a second coil layer provided between the first coil layer and the third coil layer so as to be adjacent thereto, the second coil layer having a second winding wound in a spiral shape,
a cross-sectional area of at least one winding constituting the second coil layer is larger than a cross-sectional area of at least one winding constituting the first coil layer and the third coil layer;
a gap is formed between at least some of the second windings adjacent to each other in the longitudinal direction;
the second coil layer is adjacent to both the first coil layer and the third coil layer over the entire length in the longitudinal direction;
A conductor is provided in the gap formed between the second windings.
Multilayer coil body. 5. The multilayer coil body according to claim 1, wherein a conductor is provided in the gap formed between the second windings.