Catheter

Abstract

A catheter (1) equipped with: an outer tube (10) which has a distal end (10a), a proximal end (10b) and a lumen (11) extending in a longitudinal direction (x); a bag-shaped body (20) which is provided at a distal part of the outer tube (10) and formed into an annular shape, said bag-shaped body (20) having a part having a smaller outer diameter than the outer tube (10); and a channel (30) through which a fluid can be injected into the bag-shaped body (20), wherein, when the bag-shaped body (20) is pressurized at a preset pressure by the injection of a fluid into the channel (30), the minimum inner diameter of the bag-shaped body (20) is larger than the minimum inner diameter of the bag-shaped body (20) in the state where the bag-shaped body (20) is not pressurized by the injection of the fluid into the channel (30).

Description

catheter

[0001] The present invention relates to a catheter.

[0002] For example, a resin tube is used to transport a medical device such as a balloon or a stent to a treatment site. Specifically, the medical device is placed inside the resin tube and inserted into a body cavity such as a blood vessel, and then transported to the treatment site. If the resin tube used in this case has a simple cylindrical shape, there is a problem that the tip of the tube hits the wall of the body cavity, damaging the wall or reducing its passability.

[0003] Patent Document 1 describes a catheter that can reduce damage to the walls of a body cavity. The catheter has a long, elastic tubular member with at least one lumen. A soft, deformable tip member is attached to the distal end of the catheter, and the tip member expands in outer diameter and increases in contact area when pressed against a relatively stationary surface. This makes it possible to reduce the pressure or force per unit area applied to the tissue.

[0004] Patent Document 2 describes a medical technical instrument that is easy to operate. The instrument includes a longitudinally elongated, flexible inner body, a longitudinally elongated outer envelope surrounding the inner body at least partially on the circumferential side, and a device for transitioning the instrument from a flexible state to a rigid state and vice versa. The inner body is formed in a double-tube shape, with an inner tube forming an inner wall and an outer tube forming an outer wall and concentrically surrounding the inner tube. The device for transitioning the instrument from a flexible state to a rigid state and vice versa applies pressure to the envelope by increasing the pressure in the annular gap to radially expand the outer tube, thereby transitioning the instrument to a rigid state, and is described as being easy to operate. It also describes that the outer diameter of the double-tube inner body increases, but the size of the internal space of the inner body remains fixed.

[0005] Japanese Patent Application Laid-open No. 60-040069 Special Publication No. 2009-505700

[0006] However, the catheter described in Patent Document 1 prevents damage to the body cavity by expanding the outer diameter of the tip part, and the configuration of the catheter described in Patent Document 1 does not solve the problem that the expanded tip part is prone to getting caught on the wall of the body cavity, making it difficult to pass through the body cavity.

[0007] Furthermore, the medical technology instrument described in Patent Document 2 improves operability by applying pressure to expand the outer diameter, thereby creating a rigid state, and the expanded diameter portion is prone to getting caught on the wall of the body cavity, so there is still room for improvement in terms of improving passability through the body cavity.

[0008] Furthermore, in both the catheter of Patent Document 1 and the medical technical instrument of Patent Document 2, a medical device such as a balloon or stent is transported to the treatment site, which is the target of treatment, and then the medical device is placed on the treatment site, so it is necessary to ensure an inner diameter large enough to allow the medical device to pass through.

[0009] The present invention has been made in consideration of the above circumstances, and its purpose is to provide a catheter that can easily prevent damage to the wall of a body cavity when transported to a treatment site and can also easily improve passability within the body cavity.

[0010] One embodiment of the catheter of the present invention that can solve the above problems is as follows: [1] A catheter comprising: an outer tube having a distal end and a proximal end and having a lumen extending in the longitudinal direction, a bag-like body provided at the distal portion of the outer tube, the bag-like body being formed in an annular shape and having a portion with an outer diameter smaller than that of the outer tube, and a flow path through which a fluid can be injected into the bag-like body, wherein the minimum inner diameter of the bag-like body when pressurized to a predetermined pressure by injecting a fluid into the flow path is larger than the minimum inner diameter of the bag-like body when not pressurized by injecting a fluid into the flow path.

[0011] First, the catheter is delivered to the treatment site without injecting fluid into the flow path. This maintains the small outer diameter of the portion of the bag-shaped body that is smaller than the outer tube, making it less likely to get caught on the wall of the body cavity and making it easier to prevent the catheter from damaging the wall of the body cavity when delivered to the treatment site. This also makes it easier to improve the catheter's passability through the body cavity. Furthermore, after the catheter reaches the treatment site, fluid is injected into the flow path, pressurizing the bag-shaped body and increasing the minimum inner diameter of the bag-shaped body compared to before pressurization. This makes it easier to protrude the medical device from the expanded diameter portion, even when a medical device such as a balloon, stent, basket, or needle is placed in the lumen of the outer tube and delivered to the treatment site.

[0012] The catheter of the present invention is preferably one of the following [2] to

[18] . [2] The catheter according to [1], wherein the bag-shaped body has an inner surface facing inward and an outer surface facing outward when no pressurization is being applied by injecting a fluid into the flow channel. [3] The catheter according to [2], wherein, when the bag-shaped body changes from a state where no pressurization is being applied by injecting a fluid into the flow channel to a state where it is pressurized at a predetermined pressure by injecting a fluid into the flow channel, the elongation rate of the length from the distal end to the proximal end of the inner surface is greater than the elongation rate of the length from the distal end to the proximal end of the outer surface. [4] The catheter according to [2] or [3], wherein, in a cross section parallel to the longitudinal direction, an angle formed between the inner surface and the outer surface when no pressurization is being applied by injecting a fluid into the flow channel is an acute angle. [5] The catheter according to any one of [2] to [4], wherein, in a cross section parallel to the longitudinal direction, an angle formed between the inner surface and the outer surface when it is pressurized at a predetermined pressure by injecting a fluid into the flow channel is an acute angle. [6] The catheter according to any one of [2] to [5], wherein the elongation rate of the length from the distal end to the proximal end of the inner surface portion when the bag-shaped body changes from a state in which it is not pressurized by injecting a fluid into the flow path to a state in which it is pressurized at a predetermined pressure by injecting a fluid into the flow path is greater than the elongation rate of the length from the distal end to the proximal end of the outer tube. [7] The catheter according to any one of [1] to [6], wherein the outer tube has a wall forming a lumen, and the flow path is formed within the wall of the outer tube. [8] The catheter according to [7], wherein the outer tube has an outer tube and an inner tube disposed in the lumen of the outer tube, and the flow path is a space defined by the inner surface of the outer tube and the outer surface of the inner tube. [9] The catheter according to any one of [1] to [8], wherein the bag-shaped body has an internal space communicating with the flow path.

[10] The catheter according to [9], wherein the internal space does not communicate with the lumen of the outer tube.

[11] The catheter according to any one of [1] to

[10] , wherein the bag-shaped body is provided distal to the distal end of the outer tube and has a tapered portion in which the outer diameter decreases toward the distal side.

[12] The catheter according to any one of [1] to

[11] , which has a radiopaque marker in at least one of the sac-shaped body and a region of the outer tube extending 10 cm proximally from the distal end.

[13] The catheter according to any one of [1] to

[12] , which has a tapered region in a proximal portion of the outer tube, the radial length of which, when observed from a direction perpendicular to the longitudinal direction, decreases proximally.

[14] The catheter according to

[13] , further comprising a first tubular member having a maximum outer diameter smaller than that of the outer tube and having a lumen extending in the longitudinal direction, wherein a distal portion of the first tubular member is fixed to a proximal portion of the tapered region, and the lumen of the first tubular member communicates with the flow path.

[15] The catheter according to any one of [1] to

[14] , which comprises: an inner tube disposed in the lumen of the outer tube in a state movable relative to the outer tube; and an expansion member provided in a distal portion of the inner tube and expanding in the radial direction.

[16] The catheter according to

[15] , further comprising a control mechanism for suppressing longitudinal movement of the inner tube in the lumen of the outer tube.

[17] The catheter according to

[15] or

[16] , wherein the expansion member is a balloon or a stent having a coating layer formed on its outer surface.

[18] The catheter according to

[17] , wherein the coating layer contains a physiologically active agent.

[0013] The catheter of the present invention makes it easy to project medical devices such as balloons, stents, baskets, and needles, even when transporting the devices to a treatment site, makes it easy to prevent damage to the wall of the body cavity when transporting the devices to the treatment site, and makes it easy to improve passability within the body cavity.

[0014] 1 shows a side view of an example of a catheter according to an embodiment of the present invention. 1 shows an enlarged cross-sectional view of the distal side of the catheter shown in FIG. 1. 2 shows a cross-sectional end view taken along line III-III of the catheter shown in FIG. 2. 3 shows an enlarged cross-sectional view of the distal side of the catheter shown in FIG. 1, showing a state in which pressurization by injection of a fluid into the flow path is not being performed. 4 shows a cross-sectional end view taken along line V-V of the catheter shown in FIG. 4. 4 shows a cross-sectional view of the catheter shown in FIG. 4 when pressurized to a predetermined pressure by injection of a fluid into the flow path. 5 shows a cross-sectional view of a modified example of the catheter shown in FIG. 4. 6 shows a cross-sectional end view taken along line VIII-VIII of the catheter shown in FIG. 7. 7 shows a cross-sectional view of another modified example of the catheter shown in FIG. 4. 8 shows a cross-sectional end view taken along line X-X of the catheter shown in FIG. 9. 9 shows a cross-sectional view (partially a side view) of another modified example of the catheter shown in FIG. 4. 10 shows a cross-sectional end view taken along line XII-XII of the catheter shown in FIG. 11. 11 shows a cross-sectional end view (partially a side view) of the catheter shown in FIG. 11 when pressurized to a predetermined pressure by injection of a fluid into the flow path.

[0015] The present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the illustrated examples, and appropriate modifications can be made within the scope of the above and below-described purpose, and all such modifications are within the technical scope of the present invention. In each drawing, hatching, symbols, etc. may be omitted for convenience. In such cases, reference should be made to the specification or other drawings. Furthermore, the dimensions of various parts in the drawings may differ from their actual dimensions, as priority is given to helping understand the features of the present invention.

[0016] One embodiment of the catheter of the present invention comprises an outer tube having a distal end and a proximal end and a lumen extending in the longitudinal direction; a bag-like body provided in the distal portion of the outer tube, the bag-like body being formed in an annular shape and having a portion with an outer diameter smaller than that of the outer tube; and a flow path through which a fluid can be injected into the bag-like body, wherein the minimum inner diameter of the bag-like body when it is pressurized to a predetermined pressure by injecting a fluid into the flow path is larger than the minimum inner diameter of the bag-like body when it is not pressurized by injecting a fluid into the flow path.

[0017] The overall configuration of a catheter according to an embodiment of the present invention will be described with reference to Figures 1 to 13. Figures 1, 2, 4, 6, 7, 9, 11, and 13 show a catheter 1 having an outer tube 10 and a bag-shaped body 20 provided in the distal portion of the outer tube 10. In these figures, the longitudinal direction of the outer tube 10 is indicated by x, and the radial direction is indicated by y. The radial direction y is a direction perpendicular to the longitudinal direction x, but here only one direction perpendicular to the longitudinal direction x is shown.

[0018] In this specification, the proximal side refers to the side closest to the user in the extension direction of the outer tube 10, and the distal side refers to the side opposite the proximal side, i.e., the side to be treated. Furthermore, the distal portion of each member refers to the distal half of each member, and the proximal portion of each member refers to the proximal half of each member.

[0019] Fig. 1 is a side view showing an example of a catheter according to an embodiment of the present invention. Fig. 2 is an enlarged cross-sectional view of the distal side of the catheter 1 shown in Fig. 1. Fig. 3 is a cross-sectional end view of the catheter 1 shown in Fig. 2 taken along line III-III. Note that Figs. 1 to 3 show a state in which pressurization by injection of a fluid into the flow path has not been performed.

[0020] 1 and 2, the catheter 1 has an outer tube 10. The outer tube 10 has a distal end 10a and a proximal end 10b, and has an inner lumen 11 extending in the longitudinal direction x.

[0021] 1 and 2, a bag-like body 20 is provided at the distal portion of the outer tube 10. As shown in Figures 1 to 3, the bag-like body 20 is a bag-like member formed in an annular shape, and has a portion whose outer diameter is smaller than that of the outer tube 10. It is preferable that the bag-like body 20 has an annular shape when viewed in the longitudinal direction x.

[0022] 2, the catheter 1 has a flow path 30. The flow path 30 is a space through which a fluid can pass when the fluid is injected into the bag-like body 20.

[0023] Fig. 4 is an enlarged cross-sectional view of the distal end of the catheter 1 shown in Fig. 1, showing a state in which pressurization due to fluid injection into the flow path 30 has not been performed. Fig. 5 is a cross-sectional end view of the catheter shown in Fig. 4 taken along line V-V. Fig. 6 is a cross-sectional view of the catheter 1 shown in Fig. 4 when fluid is injected into the flow path 30 of the catheter 1, resulting in a state in which the catheter 1 is pressurized to a predetermined pressure.

[0024] As shown in Figures 4 and 6, the catheter 1 is configured so that the minimum inner diameter of the bag-shaped body 20 when it is pressurized to a predetermined pressure by injecting a fluid into the flow path 30 is larger than the minimum inner diameter of the bag-shaped body 20 when it is not pressurized by injecting a fluid into the flow path 30.

[0025] First, the catheter 1 is transported to the treatment site without injecting fluid into the flow path 30. In the example described above, the catheter 1 is transported to the treatment site in the state shown in FIG. 4 . This maintains the small outer diameter of the portion of the bag-shaped body 20 that is smaller than the outer tube 10, making it less likely to get caught on the wall of the body cavity. This makes it easier to prevent the catheter 1 from damaging the wall of the body cavity when transported to the treatment site. This also makes it easier to improve passability through the body cavity. Furthermore, after the catheter 1 reaches the treatment site, fluid is injected into the flow path 30, pressurizing the bag-shaped body 20 and increasing the minimum inner diameter of the bag-shaped body 20 compared to before pressurization. In the example described above, the catheter 1 is in the state shown in FIG. 6 . This makes it easier to protrude the medical device from the expanded diameter portion, even when a medical device such as a balloon, stent, basket, or needle is placed in the lumen 11 of the outer tube 10 and transported to the treatment site.

[0026] The outer tube 10 is preferably flexible because it is inserted into the body, allowing it to be deformed to conform to the shape of the body cavity. In addition, the outer tube 10 is preferably elastic so as to maintain its shape.

[0027] The outer tube 10 may be a hollow body formed by arranging one or more wires in a predetermined pattern; a hollow body with a resin coating on at least one of the inner and outer surfaces; a resin tube; or a combination thereof, such as a combination of these, connected in the longitudinal direction. Examples of hollow bodies with wires arranged in a predetermined pattern include tubular bodies having a mesh structure formed by simply crossing or weaving wires, and coils formed by winding wires. The wires may be one or more solid wires or one or more twisted wires. Resin tubes can be manufactured, for example, by extrusion molding. When the outer tube 10 is a resin tube, it may be composed of a single layer or multiple layers. A portion of the outer tube 10 in the longitudinal direction x or circumferential direction may be composed of a single layer, and the other portion may be composed of multiple layers.

[0028] The outer tube 10 can be made of, for example, a synthetic resin such as a polyolefin resin (e.g., polyethylene or polypropylene), a polyamide resin (e.g., nylon), a polyester resin (e.g., PET), an aromatic polyether ketone resin (e.g., PEEK), a polyether polyamide resin, a polyurethane resin, a polyimide resin, or a fluororesin (e.g., PTFE, PFA, ETFE), or a metal such as stainless steel, carbon steel, or a nickel-titanium alloy. These may be used alone or in combination of two or more.

[0029] The outer surface of the outer tube 10 is preferably coated with a hydrophilic polymer, which makes it easier to insert the outer tube 10 into a body cavity. Examples of hydrophilic polymers include poly (2-hydroxyethyl methacrylate), polyacrylamide, polyvinylpyrrolidone, maleic anhydride copolymers such as methyl vinyl ether-maleic anhydride copolymers, and polyethylene glycol.

[0030] The inner surface of the outer tube 10 preferably has a portion made of a fluororesin or a polyolefin resin. Only a portion of the inner surface of the outer tube 10 may be made of a fluororesin or a polyolefin resin, or the entire inner surface of the outer tube 10 may be made of a fluororesin or a polyolefin resin. This allows the outer tube 10 to slide easily over members placed in the lumen 11 of the outer tube 10, making it easier to improve the operability of the catheter 1.

[0031] The outer diameter of the outer tube 10 can be, for example, 1.0 mm or more, 1.1 mm or more, 1.2 mm or more, etc. The outer diameter of the outer tube 10 can be, for example, 5.0 mm or less, 4.0 mm or less, 3.0 mm or less, etc., but is preferably 2.0 mm or less.

[0032] The inner diameter of the outer tube 10 can be, for example, 4.0 mm or less, 3.8 mm or less, 3.5 mm or less, etc. The inner diameter of the outer tube 10 can be, for example, 0.4 mm or more, 0.5 mm or more, 0.6 mm or more, etc., but is preferably 0.8 mm or more, and more preferably 1.2 mm or more. The inner diameter of the outer tube 10 is also preferably large enough to allow the inner tube 50 having the expansion member 60, which will be described later, to pass through.

[0033] As shown in FIG. 2, the outer tube 10 can be configured to have a distal opening 11a and a proximal opening 11b at the distal end 10a and the proximal end 10b, respectively, which connect the inner cavity 11 of the outer tube 10 to the outside of the outer tube 10.

[0034] As shown in Figures 1 and 2, the outer tube 10 can be configured to have a tapered region 13 in the proximal portion of the outer tube 10, whose length in the radial direction y when observed from a direction perpendicular to the longitudinal direction x of the outer tube 10 decreases toward the proximal side.

[0035] 2 , it is preferable that a proximal opening 11b that communicates between the lumen 11 of the outer tube 10 and the outside of the outer tube 10 is formed in the reduced-diameter region 13, and it is more preferable that the proximal opening 11b that communicates between the lumen 11 of the outer tube 10 and the outside of the outer tube 10 is formed in a portion that slopes so that the length in the radial direction y when observed from a direction perpendicular to the longitudinal direction x decreases toward the proximal side. With this configuration, for example, medical devices such as a guide wire, balloon, stent, basket, needle, etc., which will be described later, can be inserted into and removed from the outer tube 10 through the proximal opening 11b.

[0036] As shown in Figures 1 and 2, the catheter 1 further includes a first tubular member 40 having a maximum outer diameter smaller than the maximum outer diameter of the outer tube 10 and an inner lumen 41 extending in the longitudinal direction x of the outer tube 10, the distal portion of the first tubular member 40 being fixed to the proximal portion of the reduced diameter region 13, and the inner lumen 41 of the first tubular member 40 being connected to the flow path 30.

[0037] The first cylindrical member 40 is a cylindrical member having an inner lumen 41 and a maximum outer diameter smaller than the maximum outer diameter of the outer tube 10. The minimum outer diameter of the first cylindrical member 40 may also be smaller than the minimum outer diameter of the outer tube 10.

[0038] The outer diameter of the first cylindrical member 40 can be, for example, 0.60 mm or more, 0.65 mm or more, 0.70 mm or more, etc. The outer diameter of the first cylindrical member 40 can be, for example, 3.00 mm or less, 2.95 mm or less, 2.90 mm or less, etc., but is preferably 1.00 mm or less.

[0039] The inner diameter of the first cylindrical member 40 can be, for example, 2.50 mm or less, 2.45 mm or less, 2.35 mm or less, etc. The inner diameter of the first cylindrical member 40 can be, for example, 0.30 mm or more, 0.35 mm or more, 0.40 mm or more, etc., but is preferably 0.50 mm or more.

[0040] The length from the distal end of the first tubular member 40 to the proximal end of the first tubular member 40 can be, for example, 100 mm or more, 150 mm or more, 200 mm or more, etc. Furthermore, the length from the distal end of the first tubular member 40 to the proximal end of the first tubular member 40 can be, for example, 2400 mm or less, 2350 mm or less, 2300 mm or less, etc.

[0041] As described above, in the embodiment in which the first cylindrical member 40 is provided, the length from the distal end 10a of the outer tube 10 to the proximal end 10b of the outer tube 10 can be, for example, 30 mm or more, 35 mm or more, 40 mm or more, etc. Furthermore, the length from the distal end 10a of the outer tube 10 to the proximal end 10b of the outer tube 10 can be, for example, 700 mm or less, 650 mm or less, 600 mm or less, etc.

[0042] The first cylindrical member 40 can be made of the same synthetic resin, metal, or the like as the outer tube 10. The first cylindrical member 40 and the outer tube 10 may be made of the same material or different materials.

[0043] It is preferable that a lubricating coating layer containing PTFE, PFA, or the like is formed on the outer surface of the first tubular member 40. This makes it easier to insert the first tubular member 40 into a body cavity.

[0044] The first tubular member 40 may be provided with a position indication marker to indicate the length of the inserted portion when the catheter 1 is inserted into a body cavity from the distal end thereof. The position indication marker may be formed, for example, by inserting the first tubular member 40 into the lumen of a marker tube and welding the marker thereto, or may be formed by peeling off a portion of the lubricious coating layer containing the above-mentioned PTFE, PFA, or the like.

[0045] The position indication markers can be provided, for example, at positions 600 mm, 900 mm, 1200 mm, etc. from the distal end of the catheter 1.

[0046] Preferably, the distal portion of the first tubular member 40 and the proximal portion of the tapered region 13 are fixed together, and more preferably, the distal end of the first tubular member 40 and the proximal end of the tapered region 13 are fixed together, so that the lumen 41 of the first tubular member 40 communicates with the flow path 30. Preferably, the lumen 41 of the first tubular member 40 does not communicate with the lumen 11 of the outer tube 10.

[0047] 1 , the catheter 1 preferably further includes a hub 42 at the proximal end of the first tubular member 40. The hub 42 has a port therein that communicates with the lumen 41 of the first tubular member 40, and is a member used when injecting a fluid into the lumen 41 of the first tubular member 40.

[0048] Although not shown, the proximal end of the outer tube 10 may be directly connected to the hub 42. In this case, the hub 42 may have a port therein that communicates with the flow path 30, allowing fluid to be injected into the flow path 30.

[0049] The bag-shaped body 20 may be made of the same synthetic resin, metal, or the like as the outer tube 10 .

[0050] As shown in Figures 1 and 2, the proximal portion of the bag-like body 20 may be connected to the distal portion of the outer tube 10, or the proximal end of the bag-like body 20 may be connected to the distal end 10a of the outer tube 10.

[0051] The portion of the bag-shaped body 20 whose outer diameter is smaller than that of the outer tube 10 is preferably located in the distal portion of the bag-shaped body 20, more preferably at the distal end of the bag-shaped body 20, and even more preferably at the distal end of the bag-shaped body 20. This makes it easier to maintain the small outer diameter, particularly at the distal end of the bag-shaped body 20, making it less likely to get caught on the wall of the body cavity and making it easier to prevent the catheter 1 from damaging the wall of the body cavity when being transported to the treatment site. It also makes it easier to improve passability within the body cavity.

[0052] The bag-shaped body 20 is formed in an annular shape, but may also have a hollow truncated cone shape, for example, as shown in Figures 1 to 3. As shown in Figures 2 and 3, the bag-shaped body 20 is formed in an annular shape and may have an inner lumen 25 that communicates with the outside of the bag-shaped body 20. As shown in Figure 2, it is preferable that the inner lumen 25 of the bag-shaped body 20 and the inner lumen 11 of the outer tube 10 communicate with each other.

[0053] The length in the longitudinal direction x of the bag-shaped body 20 when it is not pressurized by injecting a fluid into the flow path 30 may be the same as or different from the length in the longitudinal direction x of the bag-shaped body 20 when it is pressurized at a predetermined pressure by injecting a fluid into the flow path 30.

[0054] The length of the bag-shaped body 20 in the longitudinal direction x when no pressure is applied by injecting a fluid into the flow path 30 can be, for example, 1 mm or more, 3 mm or more, 5 mm or more, etc. The length of the bag-shaped body 20 in the longitudinal direction x when no pressure is applied by injecting a fluid into the flow path 30 can be, for example, 20 mm or less, 18 mm or less, 15 mm or less, etc.

[0055] The length in the longitudinal direction x of the bag-shaped body 20 when it is pressurized to a predetermined pressure by injecting a fluid into the flow path 30 can be, for example, 1 mm or more, 3 mm or more, 5 mm or more, etc. The length in the longitudinal direction x of the bag-shaped body 20 when it is pressurized to a predetermined pressure by injecting a fluid into the flow path 30 can be, for example, 20 mm or less, 18 mm or less, 15 mm or less, etc.

[0056] The minimum inner diameter of the bag-shaped body 20 in a state where pressurization by injecting a fluid into the flow path 30 is not performed is preferably a size that allows a guide wire to be inserted. The minimum inner diameter of the bag-shaped body 20 in a state where pressurization by injecting a fluid into the flow path 30 is not performed may be 30% or more, 35% or more, or 40% or more of the inner diameter of the outer tube 10. The minimum inner diameter of the bag-shaped body 20 in a state where pressurization by injecting a fluid into the flow path 30 is not performed may be 70% or less, 65% or less, or 60% or less of the inner diameter of the outer tube 10. The minimum inner diameter of the bag-shaped body 20 in a state where pressurization by injecting a fluid into the flow path 30 is not performed may be, for example, 0.30 mm or more, 0.35 mm or more, 0.40 mm or more, etc. Furthermore, the minimum inner diameter of the bag-shaped body 20 in a state where pressurization by injecting a fluid into the flow path 30 is not performed may be, for example, 2.00 mm or less, 1.95 mm or less, 1.90 mm or less, etc.

[0057] It is preferable that the inner diameter of the bag-shaped body 20 when no pressure is applied by injecting a fluid into the flow path 30 is smallest at the distal end of the bag-shaped body 20 .

[0058] The minimum outer diameter of the bag-shaped body 20 in a state where pressurization by injecting a fluid into the flow path 30 is not performed can be, for example, 0.31 mm or more, 0.36 mm or more, 0.41 mm or more, etc. Furthermore, the minimum outer diameter of the bag-shaped body 20 in a state where pressurization by injecting a fluid into the flow path 30 is not performed can be, for example, 3.00 mm or less, 2.90 mm or less, 2.80 mm or less, etc.

[0059] It is preferable that the outer diameter of the bag-shaped body 20 is smallest at the distal end thereof when no pressure is applied by injecting a fluid into the flow path 30 .

[0060] When medical devices such as a balloon, stent, basket, or needle are placed in the lumen 11 of the outer tube 10 and transported to a treatment site, the minimum inner diameter of the bag-shaped body 20 when it is pressurized to a predetermined pressure by injecting a fluid into the flow path 30 is preferably set to a size that allows these medical devices to protrude from the bag-shaped body 20. The minimum inner diameter of the bag-shaped body 20 when it is pressurized to a predetermined pressure by injecting a fluid into the flow path 30 can be, for example, 4.0 mm or less, 3.8 mm or less, 3.5 mm or less, etc. The minimum inner diameter of the bag-shaped body 20 when it is pressurized to a predetermined pressure by injecting a fluid into the flow path 30 can be, for example, 0.4 mm or more, 0.5 mm or more, 0.6 mm or more, etc., but is preferably 0.8 mm or more, and more preferably 1.2 mm or more.

[0061] It is preferable that the inner diameter of the bag-shaped body 20 be smallest at the distal end or proximal end of the bag-shaped body 20 when the bag-shaped body 20 is pressurized to a predetermined pressure by injecting a fluid into the flow path 30.

[0062] In a state where pressurization by injection of a fluid into the flow path 30 is not performed, it is preferable that the bag-shaped body 20 does not have an outer diameter larger than the outer diameter of the outer tube 10. This configuration reduces the outer diameter of the distal end side of the catheter 1. This makes it less likely that the catheter 1 will get caught on the wall of the body cavity, making it easier to prevent the catheter 1 from damaging the wall of the body cavity when transported to the treatment site and also making it easier to improve passability within the body cavity.

[0063] When the state changes from a state in which no pressurization is being performed by injecting a fluid into the flow path 30 to a state in which pressurization is being performed at a predetermined pressure by injecting a fluid into the flow path 30, the bag-shaped body 20 may have an outer diameter that is approximately the same as or larger than the outer diameter of the outer tube 10. Note that when the state changes from a state in which no pressurization is being performed by injecting a fluid into the flow path 30 to a state in which pressurization is being performed at a predetermined pressure by injecting a fluid into the flow path 30, the outer diameter of the distal end of the bag-shaped body 20 may be smaller than the outer diameter of the outer tube 10.

[0064] As shown in Figures 2 to 4, when no pressure is applied by injecting a fluid into the flow path 30, the bag-shaped body 20 can be configured to have an inner surface portion 21 facing inward and an outer surface portion 22 facing outward.

[0065] The thickness of the inner surface portion 21 in a state where pressurization by injecting a fluid into the flow path 30 is not performed can be, for example, 0.005 mm or more, 0.006 mm or more, 0.007 mm or more, etc. Furthermore, the thickness of the inner surface portion 21 in a state where pressurization by injecting a fluid into the flow path 30 is not performed can be 0.100 mm or less, 0.090 mm or less, 0.080 mm or less, etc. Furthermore, the thickness of the inner surface portion 21 in a state where pressurization by injecting a fluid into the flow path 30 is not performed can be the same as the thickness of the expansion member 60.

[0066] The thickness of the proximal end of the outer surface portion 22 in a state where pressurization by injection of a fluid into the flow path 30 is not performed can be, for example, 0.010 mm or more, 0.015 mm or more, 0.020 mm or more, etc. Furthermore, the thickness of the proximal end of the outer surface portion 22 in a state where pressurization by injection of a fluid into the flow path 30 is not performed can be 0.500 mm or less, 0.450 mm or less, 0.400 mm or less, etc. Furthermore, as will be described later, in the case where the outer tube 10 has an outer cylinder 110 and an inner cylinder 120, the thickness of the proximal end of the outer surface portion 22 in a state where pressurization by injection of a fluid into the flow path 30 is not performed may be the same as the thickness of the outer cylinder 110.

[0067] In order to configure the bag-shaped body 20 so that the minimum inner diameter of the bag-shaped body 20 when it is pressurized to a predetermined pressure by injecting a fluid into the flow path 30 is larger than the minimum inner diameter of the bag-shaped body 20 when it is not pressurized by injecting a fluid into the flow path 30, it is preferable that the elongation percentage (%) of the length from the distal end 21 a to the proximal end 21 b of the inner surface portion 21 when the bag-shaped body 20 goes from a state where it is not pressurized by injecting a fluid into the flow path 30 to a state where it is pressurized to a predetermined pressure by injecting a fluid into the flow path 30 is larger than the elongation percentage (%) of the length from the distal end 22 a to the proximal end 22 b of the outer surface portion 22. The elongation percentage (%) is (the length of each portion after pressurization) ÷ (the length of each portion before pressurization), and this also applies to cases in the following description where elongation percentage (%) is used without any special explanation. By configuring the inner surface portion 21 so that the elongation rate (%) of the length from the distal end 21a to the proximal end 21b is greater than the elongation rate (%) of the length from the distal end 22a to the proximal end 22b of the outer surface portion 22, when a fluid is injected into the flow path 30, the inner surface portion 21, which is more elongate than the outer surface portion 22, stretches, and the inner diameter of the bag-shaped body 20 tends to become larger than before pressurization. In the example described above, the catheter 1 tends to change from the state shown in Fig. 4 to the state shown in Fig. 6. This makes it easier to protrude a medical device such as a balloon, stent, basket, or needle from the expanded diameter portion, even when the medical device is placed in the lumen 11 of the outer tube 10 and transported to a treatment site.

[0068] The inner surface portion 21 and the outer surface portion 22 may be made of the same material or different materials.

[0069] When the inner surface portion 21 and the outer surface portion 22 are made of the same material, for example, the thickness of the inner surface portion 21 shown in Figures 2 and 3 is preferably formed thinner than the outer surface portion 22. This allows the inner surface portion 21 to stretch more easily than the outer surface portion 22, so that when a fluid is injected into the flow path 30, the inner surface portion 21 of the bag-shaped body 20 stretches, making the inner diameter of the bag-shaped body 20 more likely to become larger than before pressurization. In the example described above, the catheter 1 is likely to change from the state shown in Figure 4 to the state shown in Figure 6. This makes it easier to protrude the medical device from the expanded diameter portion, even when a medical device such as a balloon, stent, basket, or needle is placed in the lumen 11 of the outer tube 10 and transported to a treatment site.

[0070] When the inner surface portion 21 and the outer surface portion 22 are made of different materials, for example, it is preferable that the inner surface portion 21 be made of a material having a higher elongation rate than the outer surface portion 22. The elongation rate here refers to the elongation rate (%) measured when a sample made of the material making up the inner surface portion 21 and a sample made of the material making up the outer surface portion 22 formed to the same shape as the sample are prepared, and one end and the other end of each sample are gripped with the same gripping width and pulled with the same strength (N). This allows the inner surface portion 21 to be more elongated than the outer surface portion 22, so that when a fluid is injected into the flow path 30, the inner surface portion 21 of the bag-shaped body 20 stretches, making the inner diameter of the bag-shaped body 20 more likely to increase than before pressurization. In the example described above, the catheter 1 is more likely to change from the state shown in FIG. 4 to the state shown in FIG. 6. This makes it easier to protrude a medical device such as a balloon, stent, basket, or needle from the expanded diameter portion, even when the medical device is placed in the lumen 11 of the outer tube 10 and transported to a treatment site.

[0071] As shown in FIG. 4 , in a cross section of the outer tube 10 parallel to the longitudinal direction x, the angle α formed between the inner surface portion 21 and the outer surface portion 22 when no pressurization due to fluid injection into the flow path 30 is performed is preferably an acute angle. The angle α may be 85° or less, 80° or less, or 70° or less. The angle α may be 1° or more, 3° or more, or 5° or more. This configuration makes it easier to reduce the outer diameter of the distal end of the bag-shaped body 20, thereby making it less likely for the bag-shaped body 20 to get caught on the wall of the body cavity and making it easier to prevent the catheter 1 from damaging the wall of the body cavity when transported to the treatment site. It also makes it easier to improve passability through the body cavity.

[0072] As shown in FIG. 6 , in a cross section parallel to the longitudinal direction x of the outer tube 10, when the outer tube 10 is pressurized to a predetermined pressure by injecting a fluid into the flow path 30, the angle β formed between the inner surface portion 21 and the outer surface portion 22 is preferably an acute angle. The angle β may be 85° or less, 80° or less, or 70° or less. The angle β may be 1° or more, 3° or more, or 5° or more. This configuration makes it easier to form a thin thickness at the distal end of the bag-shaped body 20, thereby making it easier to increase the inner diameter of the distal end of the bag-shaped body 20 when the outer tube 10 is pressurized to a predetermined pressure by injecting a fluid into the flow path 30. Therefore, even when a medical device such as a balloon, stent, basket, or needle is placed in the lumen 11 of the outer tube 10 and transported to a treatment site, the medical device can be easily protruded from the expanded diameter portion.

[0073] The fluid to be introduced into the flow channel 30 is not particularly limited, but may be, for example, a liquid such as physiological saline, a contrast medium, or a mixture thereof, or a gas such as air, nitrogen, or carbon dioxide.

[0074] 4, the outer tube 10 has a wall 12 that forms the lumen 11, and the flow path 30 can be configured to be formed within the wall 12 of the outer tube 10. This configuration eliminates the need to provide a separate member for forming the flow path 30, making it easier to make the catheter 1 thinner.

[0075] 4 and 5, the outer tube 10 may have an outer cylinder 110 and an inner cylinder 120 disposed in the lumen of the outer cylinder 110, and the flow path 30 may be a space defined by an inner surface 111 of the outer cylinder 110 and an outer surface 122 of the inner cylinder 120. This configuration eliminates the need to provide a separate member for forming the flow path 30, making it easier to make the catheter 1 thinner.

[0076] The thickness of the outer cylinder 110 can be 0.010 mm or more, 0.015 mm or more, 0.020 mm or more, etc. The thickness of the outer cylinder 110 can be 0.500 mm or less, 0.450 mm or less, 0.400 mm or less, etc.

[0077] The thickness of the inner cylinder 120 can be 0.010 mm or more, 0.015 mm or more, 0.020 mm or more, etc. The thickness of the inner cylinder 120 can be 0.500 mm or less, 0.450 mm or less, 0.400 mm or less, etc.

[0078] 5, in a cross section perpendicular to the longitudinal direction x, the distance between the inner surface 111 of the outer cylinder 110 and the outer surface 122 of the inner cylinder 120 is preferably 0.01 mm or more and 1.0 mm or less, which can reduce pressure loss when delivering fluid to the distal end through the flow path 30.

[0079] The outer cylinder 110 may have a distal end and a proximal end, and may have a lumen extending in the longitudinal direction x. The same applies to the inner cylinder 120.

[0080] When the bag-shaped body 20 changes from a state in which it is not pressurized by injecting a fluid into the flow path 30 to a state in which it is pressurized to a predetermined pressure by injecting a fluid into the flow path 30, the elongation percentage (%) of the length from the distal end 21a to the proximal end 21b of the inner surface portion 21 is preferably greater than the elongation percentage (%) of the length from the distal end 10a to the proximal end 10b of the outer tube 10. This configuration is particularly preferable when the flow path 30 is formed within the wall 12 of the outer tube 10. Since the elongation percentage (%) of the bag-shaped body 20 is higher than that of the outer tube 10, the outer tube 10 can be made less likely to deform due to fluid pressure, and therefore the fluid injected into the flow path 30 can be more easily and stably supplied to the bag-shaped body 20.

[0081] Fig. 7 is a cross-sectional view showing a modification of the catheter shown in Fig. 4. Fig. 8 is an end view of the catheter shown in Fig. 7 cut along line VIII-VIII.

[0082] 7 and 8, the flow path 30 may extend linearly in the longitudinal direction x within the wall 12 of the outer tube 10. Although not shown, the flow path may be formed in a wave-like shape within the wall 12 of the outer tube 10, or may be formed in a spiral shape that circles around the lumen 11 of the outer tube 10.

[0083] It should be noted that the flow path 30 may be formed not only within the wall 12 of the outer tube 10 but also by providing a separate member.

[0084] Fig. 9 is a cross-sectional view showing another modification of the catheter shown in Fig. 4. Fig. 10 is a cross-sectional end view of the catheter 1 shown in Fig. 9 taken along line XX.

[0085] 9 and 10 , the flow path 30 may be formed by a separately provided second cylindrical member 31. The second cylindrical member is a cylindrical member having an inner cavity. In this example, the inner cavity of the second cylindrical member 31 disposed in the inner cavity 11 of the outer tube 10 is the flow path 30.

[0086] 9 and 10 , the second tubular member 31 may be disposed in the lumen 11 of the outer tube 10. By disposing the second tubular member 31 in the lumen 11 of the outer tube 10, it is possible to make the catheter 1 thinner. Although not shown, the second tubular member 31 may also be disposed on the outside of the outer tube 10.

[0087] The second cylindrical member 31 may be made of the same synthetic resin, metal, or the like as the outer tube 10. The outer tube 10, the first cylindrical member 40, and the second cylindrical member 31 may be made of the same material or different materials.

[0088] 2 and 3, the bag-shaped body 20 preferably has an internal space 23 that communicates with the flow path 30. The fluid injected into the flow path 30 can flow into the internal space 23 formed in the bag-shaped body 20.

[0089] As shown in Figures 2 and 3, the internal space 23 is a space formed within the wall of the annular bag-shaped body 20. In the example of Figures 2 and 3, more specifically, the internal space 23 is a space formed within the wall that forms the inner cavity 25 of the bag-shaped body 20. As shown in Figures 2 and 3, the internal space 23 preferably exists throughout the entire circumferential direction within the wall of the bag-shaped body 20. In other words, the internal space 23 is preferably a space that is connected in the circumferential direction within the wall of the bag-shaped body 20. Although not shown, the internal space 23 may exist only in a portion of the circumferential direction within the wall of the bag-shaped body 20.

[0090] Furthermore, it is preferable that the internal space 23 does not communicate with the lumen 11 of the outer tube 10. It is also preferable that the internal space 23 does not communicate with the lumen 25 of the bag-shaped body 20. This makes it easier for the fluid injected into the flow path 30 to efficiently flow into the internal space 23 formed in the bag-shaped body 20.

[0091] 7 and 8 , when the flow passage 30 extends linearly in the longitudinal direction x within the wall 12 of the outer tube 10, it is preferable that the internal space 23 that is continuous throughout the entire circumferential direction within the wall of the bag-shaped body 20 communicates with the linear flow passage 30. This allows the fluid injected into the flow passage 30 to be injected into the internal space 23 of the bag-shaped body 20.

[0092] 9 , when the flow path 30 is formed by the second tubular member 31, it is preferable that the distal end portions of the bag-shaped body 20 and the second tubular member 31 are fixed, and that the bag-shaped body 20 has a hole 24 that connects the flow path 30 to the internal space 23. This allows the fluid injected into the flow path 30 to be injected into the internal space 23 of the bag-shaped body 20.

[0093] As shown in Figures 1, 2, and 4, the bag-shaped body 20 is located distal to the distal end 10a of the outer tube 10 and preferably has a tapered portion with an outer diameter that decreases distally. While the bag-shaped body 20 may have a tapered portion only in a portion thereof, it is more preferable that the entire bag-shaped body 20, i.e., from the distal end to the proximal end of the bag-shaped body 20, be tapered. By transporting the catheter 1 to the treatment site in the state shown in Figure 4 without injecting a fluid into the flow path 30, the portion of the bag-shaped body 20 whose outer diameter decreases distally remains in this state, making it less likely to get caught on the wall of the body cavity and making it easier to prevent the catheter 1 from damaging the wall of the body cavity when transported to the treatment site. This also makes it easier to improve passage through the body cavity.

[0094] 9, the catheter 1 may be configured to have an X-ray opaque marker 3 on at least one of the bag-shaped body 20 and the outer tube 10 in a region extending from the distal end to a point 10 cm proximal to the bag-shaped body 20 and the outer tube 10. With this configuration, the position of the distal end of the catheter 1 can be visually confirmed using an X-ray imaging device.

[0095] The radiopaque marker 3 may be provided only on the bag-like body 20, or only in the region from the distal end 10a of the outer tube 10 to 10 cm proximal, or on both.

[0096] The shape of the radiopaque marker is preferably tubular, and examples thereof include a cylindrical shape, a polygonal cylindrical shape, a tubular shape with a notch in a C-shaped cross section, and a coil shape formed by winding a wire.

[0097] The material constituting the radiopaque marker may be, for example, a radiopaque substance such as lead, barium, iodine, tungsten, gold, platinum, iridium, stainless steel, titanium, or a cobalt-chromium alloy, and may be such that radiopaque particles such as barium sulfate are dispersed in the outer tube 10, the bag-shaped body 20, or a separately provided resin member.

[0098] Fig. 11 is a cross-sectional view showing another modification of the catheter shown in Fig. 4, but shows a side view of the guidewire 2 and second inner tube 52, which will be described later. Fig. 12 is an end view of the catheter shown in Fig. 11 cut along line XII-XII. Fig. 13 is a cross-sectional view (partially a side view) of the catheter shown in Fig. 11 when it is pressurized to a predetermined pressure by injecting a fluid into the flow path. Note that in Figs. 11 and 13, the portion of the guidewire 2 disposed in the lumen of the inner tube 50 is indicated by a dashed line.

[0099] As shown in FIGS. 11 to 13, the configuration may include an inner tube 50 disposed in the lumen 11 of the outer tube 10 in a state in which the inner tube 50 is movable relative to the outer tube 10 .

[0100] The inner tube 50 may have a lumen extending in the longitudinal direction x. The lumen of the inner tube 50 may be used as a passage for inserting the guide wire 2 or the like, as shown in Figures 11 to 13 .

[0101] As shown in Figures 11 and 13, the inner tube 50 may be configured to include a first inner tube 51 arranged in the inner cavity 11 of the outer tube 10 and a second inner tube 52 arranged in the inner cavity of the first inner tube 51.

[0102] The material constituting the inner tube 50 can be the same as that of the outer tube 10, such as a synthetic resin or metal. The material constituting the outer tube 10, the first cylindrical member 40, and the second cylindrical member 31 may be the same as or different from the material constituting the inner tube 50. The material constituting the first inner tube 51 and the second inner tube 52 may be the same as or different from the material constituting the outer tube 10, the first cylindrical member 40, and the second cylindrical member 31.

[0103] The inner surface of the second inner tube 52 preferably has a portion made of a fluororesin or a polyolefin resin. Only a portion of the inner surface of the second inner tube 52 may be made of a fluororesin or a polyolefin resin, or the entire inner surface of the second inner tube 52 may be made of a fluororesin or a polyolefin resin. This allows the second inner tube 52 to slide easily over the guidewire 2, making it easier to improve the operability of the catheter 1.

[0104] The catheter 1 may be configured to further include a control mechanism that suppresses movement of the inner tube 50 in the longitudinal direction x within the lumen 11 of the outer tube 10. With this configuration, the catheter 1 can be transported to the treatment site while the control mechanism suppresses movement of the inner tube 50 in the longitudinal direction x within the lumen 11 of the outer tube 10, making it easier to transport the catheter 1 to the treatment site.

[0105] Although not shown, one example of the control mechanism is a mode in which the first cylindrical member 40 is provided with a gripping member capable of gripping the inner tube 50. By gripping the inner tube 50 with the gripping member, it is possible to temporarily restrain movement of the inner tube 50 in the longitudinal direction x in the lumen 11 of the outer tube 10. Then, by detaching the inner tube 50 from the gripping member, it is possible to return the inner tube 50 to a state in which it is movable relative to the outer tube 10. Examples of the gripping member include a rubber member provided with a slit that grips the inner tube 50 by pinching it, and a clip made of rigid resin.

[0106] As shown in FIGS. 11 to 13, the device may be configured to include an expansion member 60 provided at the distal portion of the inner tube 50 and expandable in the radial direction y.

[0107] The expansion member 60 may be, for example, a balloon or a stent.

[0108] The balloon is preferably made of a resin. Examples of resins constituting the balloon include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, vinyl chloride resins, silicone resins, and natural rubber. These may be used alone or in combination of two or more. Among these, polyamide resins, polyester resins, and polyurethane resins are preferably used. Elastomer resins can be used from the viewpoint of thinning and flexibility of the balloon.

[0109] 11 and 13 , when the inner tube 50 has a first inner tube 51 and a second inner tube 52, and the expansion member 60 is a balloon, it is preferable that the distal end of the expansion member 60 is fixed to the distal portion of the second inner tube 52, and the proximal end of the expansion member 60 is fixed to the distal portion of the first inner tube 51. The expansion member 60 can be expanded by injecting a fluid into the lumen of the first inner tube 51.

[0110] A stent is an expandable structure, e.g., a mesh or other network structure, that includes multiple struts. Stents can be formed from a pattern of interconnected structural elements that expand and contract, for example, circumferentially and axially. Stents include coiled stents made from a single linear metal or polymeric material, stents made by cutting a metal or polymeric tube with a laser or other cutting method, stents made by welding linear segments, and stents made by weaving multiple linear metal segments.

[0111] The stent is preferably made of a shape-memory alloy or a shape-memory resin, but may also be made of, for example, stainless steel such as SUS304 or SUS316, platinum, nickel, cobalt, chromium, titanium, tungsten, aluminum, gold, silver, a Ni—Ti alloy, or a Co—Cr alloy.

[0112] The stent may be a self-expanding stent or a balloon-expandable stent.

[0113] After the catheter 1 reaches the treatment site, fluid is injected into the flow path 30, which pressurizes the bag-shaped body 20 and increases the minimum inner diameter of the bag-shaped body 20 compared to before pressurization. In the example described above, the catheter 1 changes from the state shown in Fig. 11 to the state shown in Fig. 13 by injecting fluid. As a result, after the expansion member 60 disposed in the lumen 11 of the outer tube 10 in the state shown in Fig. 11 is transported to the treatment site, the minimum inner lumen of the bag-shaped body 20 is expanded in diameter as shown in Fig. 13, making it easier to protrude the inner tube 50 equipped with the expansion member 60 from the expanded diameter portion.

[0114] The expansion member 60 preferably uses a balloon or stent having a coating layer formed on its outer surface 61. After the catheter 1 reaches the treatment site, fluid is injected into the flow path 30 to pressurize the sac-shaped body 20, increasing the minimum inner diameter of the sac-shaped body 20 compared to before pressurization. In the example described above, the catheter 1 changes from the state shown in FIG. 11 to the state shown in FIG. 13 upon fluid injection. As a result, after the balloon or stent placed in the lumen 11 of the outer tube 10 in the state shown in FIG. 11 is transported to the treatment site, the minimum lumen of the sac-shaped body 20 is expanded as shown in FIG. 13, making it easier to protrude the inner tube 50 equipped with the balloon or stent from the expanded portion. This makes it easier to prevent the coating layer formed on the outer surface 61 of the balloon or stent from peeling off when the balloon or stent is placed at the treatment site.

[0115] The coating layer can be formed by applying a coating agent to the outer surface of the balloon or stent. The coating layer may be formed only on a portion of the outer surface of the balloon or stent, or may be formed on the entire outer surface of the balloon or stent.

[0116] For example, the coating layer may include a lubricious coating agent or a biologically active agent.

[0117] Examples of lubricating coating agents include silicone-based coating agents such as silicone and polydimethylsiloxane; acrylic-based coating agents such as sodium (meth)acrylate, butyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, octyl (meth)acrylate, and 2,2,2-trifluoroethyl methacrylate; fluorine-based coating agents such as polytetrafluoroethylene; and hydrophilic coating agents such as polyvinylpyrrolidone, hyaluronic acid, and polyethylene glycol.

[0118] Examples of physiologically active agents include paclitaxel, docetaxel, sirolimus, temsirolimus, everolimus, zotarolimus, biolimus A9, cilostazol, cyclosporine, and NF-κB decoy oligonucleotides. A physiologically active agent may be used alone, or multiple physiologically active agents may be used in combination. Furthermore, a balloon or stent may be coated with only a physiologically active agent, or may be coated with a physiologically active agent to which an appropriate additive has been added.

[0119] The length from the distal end to the proximal end of the catheter 1 can be, for example, 200 mm or more, 250 mm or more, 300 mm or more, etc. The length from the distal end to the proximal end of the catheter 1 can be, for example, 2500 mm or less, 2450 mm or less, 2400 mm or less, etc.

[0120] Although not shown, the proximal end of the catheter 1 is provided with a hub 42, a controller used to operate the catheter 1, other devices, etc., and may further include a mechanism capable of fixing these components so that their relative positions do not change. Preferably, this mechanism is capable of fixing at least two of the hub 42, the controller, and other devices so that their relative positions do not change. Here, being capable of being fixed means that the relative positions of the at least two components can be fixed so that they do not change, and that the fixed state can be released so that the relative positions of the at least two components can be changed.

[0121] This application claims the benefit of priority based on Japanese Patent Application No. 2022-054634, filed on March 29, 2022. The entire contents of the specification of Japanese Patent Application No. 2022-054634, filed on March 29, 2022, are incorporated herein by reference.

[0122] 1: Catheter 2: Guidewire 3: Radiopaque marker 10: Outer tube 10a: Distal end of outer tube 10b: Proximal end of outer tube 11: Lumen of outer tube 12: Wall 13: Reduced diameter region 20: Sac-like body 21: Inner surface portion 21a: Distal end of inner surface portion 21b: Proximal end of inner surface portion 22: Outer surface portion 22a: Distal end of outer surface portion 22b: Proximal end of outer surface portion 23: Internal space 24: Hole 25: Lumen of sac-like body 30: Flow path 31: Second tubular member 40: First tubular member 41: Lumen of first tubular member 42: Hub 50: Inner tube 51: First inner tube 52: Second inner tube 60: Expansion member 61: Outer surface 110: Sheath 111: Inner surface of sheath 120: Inner tube 122: Outer surface of inner cylinder

Claims

1. an outer tube having a distal end and a proximal end and having a longitudinally extending lumen; a pouch-like body provided at a distal portion of the outer tube, the pouch-like body being formed in an annular shape and having a portion whose outer diameter is smaller than that of the outer tube; a flow path through which a fluid can be injected into the bag-shaped body, a minimum inner diameter of the bag-shaped body when the bag-shaped body is pressurized at a predetermined pressure by injecting a fluid into the flow path is larger than a minimum inner diameter of the bag-shaped body when the bag-shaped body is not pressurized by injecting a fluid into the flow path; A catheter in which the outer diameter of the bag-shaped body is equal to or smaller than the outer diameter of the outer tube when the bag-shaped body is pressurized to a predetermined pressure by injecting a fluid into the flow path.

2. 2. The catheter according to claim 1, wherein, when pressurized by injecting a fluid into the flow path, the bag-shaped body has an inner surface facing inward and an outer surface facing outward.

3. 3. The catheter according to claim 2, wherein when the bag-shaped body changes from a state in which it is not pressurized by injecting a fluid into the flow path to a state in which it is pressurized at a predetermined pressure by injecting a fluid into the flow path, the elongation rate of the length from the distal end to the proximal end of the inner surface portion is greater than the elongation rate of the length from the distal end to the proximal end of the outer surface portion.

4. 4. The catheter according to claim 2, wherein in a cross section parallel to the longitudinal direction, the angle between the inner surface and the outer surface is an acute angle when no pressure is applied by injecting a fluid into the flow channel.

5. 4. The catheter according to claim 2 or 3, wherein in a cross section parallel to the longitudinal direction, the angle between the inner surface and the outer surface is an acute angle when the catheter is pressurized to a predetermined pressure by injecting a fluid into the flow path.

6. 4. The catheter according to claim 2 or 3, wherein when the bag-shaped body changes from a state in which it is not pressurized by injecting a fluid into the flow path to a state in which it is pressurized at a predetermined pressure by injecting a fluid into the flow path, the elongation rate of the length from the distal end to the proximal end of the inner surface portion is greater than the elongation rate of the length from the distal end to the proximal end of the outer tube.

7. the outer tube has a wall defining a lumen; The catheter according to any one of claims 1 to 3, wherein the flow path is formed within the wall of the outer tube.

8. The outer tube has an outer cylinder and an inner cylinder disposed in the inner cavity of the outer cylinder, 8. The catheter according to claim 7, wherein the flow path is a space defined by the inner surface of the outer cylinder and the outer surface of the inner cylinder.

9. The catheter according to any one of claims 1 to 3, wherein the bag-shaped body has an internal space communicating with the flow path.

10. The catheter of claim 9, wherein the interior space is not in communication with the lumen of the outer tube.

11. The catheter according to any one of claims 1 to 3, wherein the bag-shaped body is provided distal to the distal end of the outer tube and has a tapered portion whose outer diameter decreases toward the distal side.

12. 4. The catheter according to claim 1, further comprising an X-ray opaque marker on at least one of the bag-shaped body and the outer tube in a region extending from the distal end to a position 10 cm proximal to the bag-shaped body and the outer tube.

13. The catheter according to any one of claims 1 to 3, wherein the proximal portion of the outer tube has a tapered region whose radial length decreases toward the proximal side when observed from a direction perpendicular to the longitudinal direction.

14. a first tubular member having a maximum outer diameter smaller than the maximum outer diameter of the outer tube and having a lumen extending in the longitudinal direction; a distal portion of the first tubular member secured to a proximal portion of the reduced diameter region; The catheter according to claim 13, wherein the lumen of the first tubular member communicates with the flow path.

15. an inner tube disposed in a lumen of the outer tube so as to be movable relative to the outer tube; The catheter according to any one of claims 1 to 3, further comprising: an expansion member provided at a distal portion of the inner tube and capable of expanding in a radial direction.

16. The catheter of claim 15, further comprising a control mechanism that restrains the longitudinal movement of the inner tube within the lumen of the outer tube.

17. 16. The catheter according to claim 15, wherein the expansion member is a balloon or a stent having a coating layer formed on its outer surface.

18. 18. The catheter of claim 17, wherein the coating layer includes a bioactive agent.