JP7575257B2 - catheter - Google Patents

Description

The present invention relates to a catheter.

For example, when treating an obstruction such as a chronic total occlusion (CTO) formed in a blood vessel, a medical device is known that improves blood flow by penetrating the hard obstruction.

Medical devices used in body cavities such as blood vessels are required to have the flexibility to move smoothly through curved body cavities, and to generate a strong propulsive force when penetrating an occlusion. One such medical device is a catheter with a spiral cut formed on the outer periphery of a long shaft along the longitudinal direction (see, for example, Patent Document 1).

The above catheter has spiral cuts that bite into biological tissue, allowing the biological tissue to be used as a guide. Therefore, for example, when penetrating an obstruction, the screw action of the catheter when rotated can be expected to impart a strong propulsive force to the long shaft.

Special Publication No. 2011-506045

However, in conventional catheters such as those described above, the spiral incision may close during catheter operation. For example, when the long shaft is pushed hard against the resistance within the body cavity, or when the long shaft passes through a curved body cavity with a small radius of curvature, the spiral incision tends to close partially or entirely. This can cause biological tissue to not bite into the closed incision, resulting in insufficient propulsive force.

The present invention was made based on the above circumstances, and its purpose is to provide a catheter that can generate sufficient and reliable propulsive force even when the hollow shaft is pushed hard or passed through a curved body cavity.

Some aspects of the present disclosure include:
(1) A hollow shaft having a slit extending helically along a longitudinal direction,
the surfaces facing each other across the slit are a first surface and a second surface,
The first surface and the second surface are movable toward and away from each other,
a catheter having a recess, the recess being located radially outwardly of a contact portion between the first surface and the second surface and opening radially outwardly, in a state in which the first surface and the second surface are in contact with each other;
(2) The catheter according to (1), wherein a surface of the recess includes a plane.
(3) The catheter according to (1) or (2), wherein a width of the recess in a direction perpendicular to a spiral direction of the slit increases radially outward.
(4) The catheter according to any one of (1) to (3), wherein the recess is formed in a stepped shape in a cross-sectional view in a direction perpendicular to the spiral direction of the slit.
(5) The catheter according to any one of (1) to (4), wherein a hole and/or a groove opening toward the outside is formed in a part of the first surface and/or the second surface of the recess.
(6) A catheter described in any one of (1) to (5) above, in which the depth of the recess in the radial direction of the hollow shaft is greater than half the opening width of the recess in a direction perpendicular to the spiral direction of the slit; and (7) a catheter described in any one of (1) to (5) above, in which the depth of the recess in the radial direction of the hollow shaft is greater than the opening width of the recess in a direction perpendicular to the spiral direction of the slit.

In this specification, "the first surface and the second surface can be brought into contact with each other" means that the first surface and the second surface can be in either a contacting state or a separated state. However, "the first surface and the second surface are in contact with each other" means that a part of the first surface and a part of the second surface are in contact with each other. "Hole" means a part with a substantially circular (including circular, elliptical, polygonal, etc.) opening and a bottom that is recessed compared to the surface surrounding the hole. "Groove" means a part with a longitudinal opening and a bottom that is recessed compared to the surface surrounding the groove (excluding the above "hole").

The present invention provides a catheter that can generate sufficient and reliable propulsive force even when the hollow shaft is pushed hard or passed through a curved body cavity.

FIG. 1 is a schematic side view showing a first embodiment. FIG. 2 is a schematic vertical cross-sectional view of an area II surrounded by a dashed line in FIG. 1, illustrating a state in which the first surface and the second surface are spaced apart from each other. 3 is a partially enlarged schematic cross-sectional view showing a state in which the first surface and the second surface of FIG. 2 are in contact with each other; FIG. FIG. 2 is a partially enlarged schematic cross-sectional view showing one embodiment of a recess. FIG. 2 is a partially enlarged schematic cross-sectional view showing one embodiment of a recess. FIG. 2 is a partially enlarged schematic cross-sectional view showing one embodiment of a recess. FIG. 4 is a partially enlarged schematic cross-sectional view showing the shape of a recess. FIG. 11 is a partially enlarged schematic cross-sectional view of a second embodiment. FIG. 11 is a partially enlarged schematic cross-sectional view of a third embodiment. FIG. 13 is a partially enlarged schematic cross-sectional view of a fourth embodiment. FIG. 2 is a schematic plan view showing one embodiment of a first surface and a second surface. FIG. 2 is a schematic plan view showing one embodiment of a first surface and a second surface. FIG. 13 is a schematic side view of a modified example.

The catheter of the present disclosure comprises a hollow shaft having a slit formed therein that extends helically along the longitudinal direction, the surfaces facing each other across the slit being a first surface and a second surface, the first surface and the second surface being movable together, and when the first surface and the second surface are in contact with each other, the hollow shaft has a recess that is located radially outward of the contact portion between the first surface and the second surface and that opens radially outward.

In this specification, the term "slit portion" refers to the portion where the first surface and the second surface face each other, regardless of whether the first surface and the second surface are in contact with each other (whether a slit exists or not).

The first to fourth embodiments will be described below with reference to the drawings, but the present invention is not limited to the following embodiments. The dimensions of the catheter shown in each drawing are shown to facilitate understanding of the implementation, and do not correspond to the actual dimensions. In each drawing, the left side is the tip side (distal side) that is inserted into the body, and the right side is the base side (proximal side, hand side) that is operated by a doctor or other technician. Figures 3 to 8 show the state in which the slit in the slit section is closed (the state in which the first surface and the second surface are in contact).

[First embodiment]
1 and 2 are schematic diagrams showing a first embodiment. As shown in Fig. 1 and Fig. 2, the catheter 1 is generally composed of a hollow shaft 11, a distal tip 21, an inner tube 31, a covering member 41, and a gripping member 51.

The hollow shaft 11 is a hollow shaft with a slit 11s that extends helically along the longitudinal direction. The slit 11s is cut out so as to penetrate the hollow shaft 11 in the radial direction.

The surfaces that face each other across the slit 11s are the first surface 111 and the second surface 112. The first surface 111 and the second surface 112 are arranged so that they can come into contact with each other and can be separated from each other. In this embodiment, the portion 111a of the first surface 111 and the portion 112a of the second surface 112 are configured so that they can come into contact with each other and can be separated from each other.

Normally, the first surface 111 (part 111a) and the second surface 112 (part 112a) are separated from each other, forming a gap 11c (see FIG. 2). On the other hand, for example, when a compressive force acts on the hollow shaft 11 along the longitudinal direction, or when the hollow shaft 11 is curved, the hollow shaft 11 is deformed, causing a part of the first surface 111 (part 111a) to come into contact with a part of the second surface 112 (part 112a) (see contact part 11b in FIG. 3). The contact part 11b can be formed around the entire circumference or part of the circumference of the hollow shaft 11.

When the first surface 111 and the second surface 112 are in contact with each other, the hollow shaft 11 has a recess located radially outside the contact portion 11b between the first surface 111 and the second surface 112 and opening radially outward. That is, when the portion 111a and the portion 112a are in contact with each other, a recess m1 is formed on the outer circumferential surface 11d of the hollow shaft 11 radially outside the contact portion 11b, the recess m1 being composed of the portion 111e other than the contact portion 11b of the first surface 111 and the portion 112e other than the contact portion 11b of the second surface 112 (see FIG. 3).

The shape of the recess m1 is not particularly limited as long as it opens toward the radial outside. The shape of the recess m1 may be configured such that, for example, the width of the recess m1 in a direction perpendicular to the spiral direction of the slit 11s increases toward the radial outside. For example, the recess m1 may be configured with one plane p11 (see FIG. 3) or two or more planes p12, p13 (see FIG. 4A) so that the cross section of the slit portion 11a is V-shaped. In addition, the recess m1 may be configured with a convex curved surface p14 (see FIG. 4B) or a concave curved surface p15 (see FIG. 4C) so that the cross section of the slit portion 11a is curved. This allows the biological tissue to be reliably engaged in the recess m1, and the propulsive force can be generated more reliably.

The depth value of the recess m1 in the radial direction of the hollow shaft 11 may be configured to be greater than 1/2 the opening width value of the recess m1 in the direction perpendicular to the spiral direction of the slit 11s. That is, as shown in FIG. 5, when the first surface 111 and the second surface 112 are in contact with each other, the depth value of the recess m1 in the radial direction of the hollow shaft 11 may be "A" and the opening width value of the recess m1 in the direction perpendicular to the spiral direction of the slit 11s may be "B", so that A>(B/2). As a result, the biological tissue bites more sharply in the radial direction, and a higher resistance (movement resistance of the hollow shaft 11 in the longitudinal direction against the biological tissue) can be obtained along the longitudinal direction, and the propulsive force of the hollow shaft 11 can be further increased.

Furthermore, the depth value of the recess m1 in the radial direction of the hollow shaft 11 may be configured to be greater than the opening width of the recess m1 in a direction perpendicular to the spiral direction of the slit 11s. In other words, when the first surface 111 and the second surface 112 are in contact with each other, the depth A of the recess m1 may be greater than the opening width B of the recess m1 (A>B). This can further increase the propulsive force of the hollow shaft 11.

When the first surface 111 and the second surface 112 are in contact with each other, the contact portion 11b is preferably configured to have a surface contact between the first surface 111 and the second surface 112. This allows the contact area between the first surface 111 and the second surface 112 at the contact portion 11b to be larger, so that the rotational force (torque) generated when the gripping member 51 described below is rotated can be transmitted more reliably to the tip side of the catheter 1, and the propulsive force of the hollow shaft 11 due to the screw action can be further increased.

The material constituting the hollow shaft 11 is preferably antithrombotic, flexible, and biocompatible, since the hollow shaft 11 is inserted into a body cavity. Examples of the material that can be used include metal materials such as stainless steel (SUS304, SUS304L, etc.) and nickel-titanium alloys; and resin materials such as polyamide, polyamide elastomer, polyolefin, polyester, polyester elastomer, polyurethane, silicone, and fluororesin.

The tip tip 21 is a hollow member extending from the tip of the hollow shaft 11 toward the tip side. The tip tip 21 can be provided, for example, as a separate body from the hollow shaft 11 and joined to the tip of the hollow shaft 11 by welding or the like. The tip tip 21 can be formed, for example, so as to taper toward the tip side.

The distal tip 21 can be formed, for example, from a material that is more flexible than the material that constitutes the hollow shaft 11. Examples of materials that constitute the distal tip 21 include resin materials such as polyurethane, polyurethane elastomer, polyamide, and polyamide elastomer. This allows the catheter 1 to move smoothly inside the body cavity while further reducing the load caused by contact with biological tissue.

The inner tube 31 is a hollow member. For example, the inner tube 31 is provided inside the distal tip 21 and the hollow shaft 11, and can be arranged from the distal end of the distal tip 21 to the proximal end of the hollow shaft 21. The inner tube 31 has an opening 31a at the distal end and an inner cavity 31h that penetrates from the opening 31a toward the proximal end. For example, a medical device such as a guidewire is inserted into the inner cavity 31h, and a fluid such as a medicinal solution is passed through the inner cavity 31h.

The inner tube 31 can be composed of, for example, a cylindrical member, a coil body, etc. In this embodiment, a cylindrical inner tube is illustrated. Note that the inner tube 31 and the hollow shaft 11 may be in contact with each other or may be spaced apart.

The material constituting the inner tube 31 is preferably antithrombotic, flexible, and biocompatible, since the inner tube 31 is inserted into a body cavity. For example, the material may be the same as the material constituting the hollow shaft 11 described above.

The catheter 1 has an inner tube 31, which allows the hollow shaft 11 to rotate smoothly around the longitudinal axis with the inner tube 31 as the axis.

The covering member 41 is a member that covers the outer periphery of the base end side of the hollow shaft 11. The covering member 41 can be provided in a portion where it is not necessary for biological tissue to be caught in the recess m1 or where such a case can be avoided. For example, the covering member 41 may be formed (covered) so as to be in close contact with the outer periphery 11d of the portion of the hollow shaft 11 in the longitudinal direction where the slit portion 11a is formed.

Examples of materials that can be used to form the covering member 41 include polyamide, polyolefin, polyester, polyurethane, silicone, and fluororesin.

The covering member 41 may be formed of a heat-shrinkable resin tube. Examples of heat-shrinkable resin materials include polyolefins; fluororesins such as FEP (fluorinated ethylene propylene) and PTFE (polytetrafluoroethylene); and PEEK (polyether ether ketone). This makes it easy to form the covering member 41 around the outer periphery of the hollow shaft 11.

The gripping member 51 is a member with which the operator grips the catheter 1. The gripping member 51 is connected, for example, to the base end of the hollow shaft 11 and has an inner lumen 51h that communicates with the inner lumen 31h. An opening 51a is formed at the base end of the inner lumen 51h. The shape of the gripping member 51 can be appropriately selected, for example, to a shape that is easy for the operator to manipulate.

Here, the lumen L is formed by the inner cavity 31h of the inner tube 31 and the inner cavity 51h of the gripping member 51. Medical instruments such as a guidewire, liquids such as medicinal fluids, etc. are inserted into this lumen L via the openings 31a, 51a.

Next, we will explain how to use the catheter 1. First, as one way of using the catheter 1, we will explain a procedure in which the catheter 1 is pushed through an obstruction such as a chronic total occlusion (CTO) formed in a blood vessel after penetrating the obstruction.

First, an introduction needle (not shown) is used to puncture the blocked area to form a through hole. Next, a guide wire (not shown) is inserted into the inner cavity of the introduction needle, and the introduction needle is then removed from the body.

Next, the base end of the guidewire is inserted into the opening 31a of the catheter 1, and the base end of the guidewire is pulled out from the opening 51a through the lumen L. Next, the hollow shaft 11 is inserted into the blood vessel following the distal tip 21, and the catheter 1 is pushed forward to the occlusion. Next, the distal tip 21 is inserted into the through-hole entrance of the occlusion, and the catheter 1 is advanced while rotating the hollow shaft 11 by operating the gripping member 51. Note that when the hollow shaft 11 is strongly pushed or passes through a curved blood vessel, the slit 11s may be blocked and the first surface 111 and the second surface 112 may come into contact. Even in such a case, the biological tissue (for example, the inner wall of the occlusion) may bite into the recess m1 formed by the above contact, and the hollow shaft 11 advances due to the screw action. Next, the guidewire is removed from the body, and the desired treatment is performed using the catheter 1.

After the treatment using the catheter 1 is completed, a guidewire (not shown) is inserted into the lumen L through the opening 51a, and the catheter 1 and the guidewire are removed from the body in that order, completing the procedure.

Next, as another example of how the catheter 1 can be used, a procedure will be described in which the catheter 1 is pushed through an obstruction such as the duodenal papilla after penetrating the obstruction when removing stones, etc.

First, an endoscope (not shown) is inserted through the mouth and advanced into the duodenum. After reaching the duodenal papilla, a guidewire (not shown) is passed from the forceps insertion port of the endoscope to the tip of the endoscope, and the tip of the guidewire is inserted into the duodenal papilla.

Next, catheter 1 is inserted from the rear end of the guidewire and advanced to the penetration site. Catheter 1 is then rotated to expand the penetration site. After expansion is complete, the catheter is removed and the desired treatment is performed (such as placing a stent and then removing the guidewire, if necessary).

As described above, because the catheter 1 has the above-mentioned configuration, even if the hollow shaft 11 is pushed in strongly or passed through a curved body cavity, the biological tissue can be caught in the recess m1 formed when the first surface 111 and the second surface 112 come into contact, and a sufficient and reliable propulsive force can be generated due to the high resistance.

As described above, the catheter 1 can generate sufficient and reliable propulsive force, and therefore can be suitably used, for example, as a dilator that expands an occlusion by using a strong propulsive force.

Second Embodiment
Fig. 6 is a partially enlarged schematic cross-sectional view of the second embodiment. As shown in Fig. 6, the catheter 2 is generally composed of a hollow shaft 12, a distal tip 21, an inner tube 31, a covering member 41, and a gripping member 51, which are not shown. The catheter 2 differs from the first embodiment in the hollow shaft 12. Note that the distal tip 21, the inner tube 31, the covering member 41, and the gripping member 51 are the same as those in the first embodiment, so the same parts are given the same reference numerals and detailed description thereof is omitted. In addition, the configuration of the hollow shaft 12 and the usage mode of the catheter 2 other than the configuration described below are the same as those in the first embodiment.

The hollow shaft 12 is a hollow member in which a slit is formed that extends in a spiral shape along the longitudinal direction. The surfaces that face each other across the slit are a first surface and a second surface, and the first surface and the second surface can be brought into contact with each other. When the first surface and the second surface are in contact with each other, the hollow shaft has a recess that is located radially outward of the contact point between the first surface and the second surface and that opens toward the radially outward direction.

In this embodiment, the surface of the recess m2 formed in the slit portion 12a is configured to include a plane p21. That is, part or all of the first and/or second surfaces of the recess m2 are configured to have a planar shape. Specifically, the slit portion 12a may have, for example, the entire surface of the recess configured with one or more planes (see Figures 3 and 4A), or may have only a part of the surface of the recess m2 that includes a plane p21, with the remaining part being formed as a curved surface p22 (see Figure 6).

As described above, the catheter 2 has the above-mentioned configuration, so that the biological tissue can be more reliably engaged in the recess m2, and the propulsive force of the hollow shaft 12 can be further increased.

[Third embodiment]
Fig. 7 is a partially enlarged schematic cross-sectional view of the third embodiment. As shown in Fig. 7, the catheter 3 is generally composed of a hollow shaft 13, a distal tip 21, an inner tube 31, a covering member 41, and a gripping member 51, which are not shown. The catheter 3 differs from the first embodiment in the hollow shaft 13. Note that the distal tip 21, the inner tube 31, the covering member 41, and the gripping member 51 are the same as those in the first embodiment, so the same parts are given the same reference numerals and detailed description thereof is omitted. In addition, the configuration of the hollow shaft 13 and the usage mode of the catheter 3 other than the configuration described below are the same as those in the first embodiment.

The hollow shaft 13 is a hollow shaped member in which a slit is formed that extends in a spiral shape along the longitudinal direction. The surfaces that face each other across the slit are a first surface and a second surface, and the first surface and the second surface can be brought into contact with each other. When the first surface and the second surface are in contact with each other, the hollow shaft has a recess that is located radially outward of the contact point between the first surface and the second surface and opens radially outward.

A part or all of the first surface and/or the second surface of the recess may include a stepped portion. In this embodiment, the first surface 131 and the second surface 132 of the recess m3 are entirely stepped when viewed in a cross section perpendicular to the spiral direction of the slit (see FIG. 7).

As described above, the catheter 3 has the above-mentioned configuration, so that the biological tissue can be more reliably engaged in the recess m3, and the propulsive force of the hollow shaft 13 can be further increased.

[Fourth embodiment]
Fig. 8 is a partially enlarged schematic cross-sectional view of the fourth embodiment. As shown in Fig. 8, the catheter 4 is generally composed of a hollow shaft 14, a distal tip 21, an inner tube 31, a covering member 41, and a gripping member 51, which are not shown. The catheter 4 differs from the first embodiment in the hollow shaft 14. Note that the distal tip 21, the inner tube 31, the covering member 41, and the gripping member 51 are the same as those in the first embodiment, so the same parts are given the same reference numerals and detailed description thereof is omitted. In addition, the configuration of the hollow shaft 14 and the usage mode of the catheter 4 other than the configuration described below are the same as those in the first embodiment.

The hollow shaft 14 is a hollow shaped member in which a slit is formed that extends in a spiral shape along the longitudinal direction. The surfaces that face each other across the slit are a first surface and a second surface, and the first surface and the second surface can be brought into contact with each other. When the first surface and the second surface are in contact with each other, the hollow shaft has a recess that is located radially outward of the contact portion between the first surface and the second surface and opens toward the radially outward direction.

A hole and/or a groove that opens to the outside may be formed in a portion of the first surface and/or the second surface of the recess. In this embodiment, a hole m41 and a groove m42 are formed in a portion of the first surface 141 and the second surface 142 of the recess m4 (see Figures 8, 9A, and 9B). Although not shown, the hole m41 and the groove m42 may be mixed on one surface.

As described above, the catheter 4 has the above-mentioned configuration, so that the biological tissue can be more reliably engaged in the recess m4 by being able to be engaged in the hole m41 and groove m42, thereby further increasing the propulsive force of the hollow shaft 14.

The present disclosure is not limited to the configurations of the above-described embodiments, but is intended to include all modifications within the scope and meaning equivalent to the claims, as set forth in the claims. Some of the configurations of the above-described embodiments may be deleted or replaced with other configurations, and other configurations may be added to the configurations of the above-described embodiments.

For example, in the first and third embodiments described above, catheters 1 and 3 having a first surface and a second surface that are geometrically symmetrical with respect to contact portion 11b and 13b were described as examples. However, as long as the above-mentioned recess is formed when the first surface and the second surface are in contact with each other, the first surface and the second surface may be geometrically asymmetrical (see, for example, recesses m2 and m4 in Figures 6 and 8).

In the first embodiment described above, the catheter 1 is exemplified in which the hollow shaft 11 has the same outer diameter along the entire longitudinal direction. However, the hollow shaft may have portions with different outer diameters along the longitudinal direction. An example of such a catheter is a dilator 5 having a hollow shaft 15 with a slit 15s formed therein and a tapered portion 15t that expands in diameter toward the base end, as shown in FIG. 10.

In the first embodiment described above, a catheter 1 is illustrated in which a single continuous slit 11s is formed along the entire longitudinal direction of the hollow shaft 11. However, the slits may be multiple, may be provided intermittently along the longitudinal direction of the hollow shaft, or may be provided only along a portion of the longitudinal direction (not shown).

In the above-described embodiment, the catheters 1, 2, 3, and 4 are described as having a distal tip 21, an inner tube 31, a covering member 41, and a gripping member 51. However, the catheter may not have at least any of the distal tip, the inner tube, the covering member, and the gripping member.

1, 2, 3, 4 Catheter 5 Dilator (catheter)
11, 12, 13, 14, 15 Hollow shaft 11s, 15s Slit 111, 121, 131, 141 First surface 112, 122, 132, 142 Second surface 11b, 12b, 13b, 14b Contact portion m1, m2, m3, m4 Recessed portion m41 Hole portion m42 Groove portion

Claims (4)

A hollow shaft having a slit extending helically along a longitudinal direction,
the surfaces facing each other across the slit are a first surface and a second surface,
The first surface and the second surface are movable toward and away from each other,
The first surface and the second surface are normally separated from each other, thereby forming a gap between the first surface and the second surface,
When the first surface and the second surface are in contact with each other, the hollow shaft has a recess that is located radially outward from a contact portion between the first surface and the second surface and opens radially outward ,
A catheter in which the cross-sectional shape of the recess in a direction perpendicular to the spiral direction of the slit is V-shaped . A hollow shaft having a slit extending helically along a longitudinal direction,
the surfaces facing each other across the slit are a first surface and a second surface,
The first surface and the second surface are movable toward and away from each other,
The first surface and the second surface are normally separated from each other, thereby forming a gap between the first surface and the second surface,
When the first surface and the second surface are in contact with each other, the hollow shaft has a recess that is located radially outward from a contact portion between the first surface and the second surface and opens radially outward ,
A catheter in which a further recessed hole and/or groove opening radially outward is formed in a portion of the first surface and the second surface that do not contact each other in the recess . 3. The catheter according to claim 1 , wherein a depth of the recess in a radial direction of the hollow shaft is greater than half a width of the opening of the recess in a direction perpendicular to the spiral direction of the slit. 3. The catheter according to claim 1 , wherein a depth of the recess in a radial direction of the hollow shaft is greater than an opening width of the recess in a direction perpendicular to the spiral direction of the slit.

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