Catheter

Abstract

This catheter (100) is provided with: a first shaft (10); a distal end member (20) configured from a sheet-like object (40) that has particles containing an X-ray opaque substance, has a folded part in the distal section, and is formed in a cylindrical shape; a second shaft (50); and a balloon (60) that has a main body part (61) that expands and contracts in the radial direction (y) of the first shaft (10), and can adjust the projection length of the main body part (61) from the first shaft (10) according to the length a patient's lesion. At least a part of the folded part is located distal to the distal end (10d) of the first shaft (10), and the inner diameter of the distal end member (20) can be expanded by unfolding the folded part by expansion of the balloon (60).

Description

catheter

[0001] The present invention relates to a catheter.

[0002] Catheters have been developed that have an expansion member that can adjust the length of the portion that expands outside the sheath to match the length of the lesion by adjusting the length of the portion that protrudes from the sheath. Such catheters can perform treatment on the lesion by adjusting the length of the portion that expands outside the sheath to match the length of the lesion.

[0003] For example, US Pat. No. 6,299,649 discloses a catheter assembly having a sheath with an expansion member disposed therein and a flexible distal tip.

[0004] US Patent No. 5,949,999 discloses a catheter having an outer sleeve with a balloon disposed therein and a flexible distal end.

[0005] US Patent No. 5,949,999 discloses a catheter having an outer sheath with an expansion member disposed therein and a flexible distal end.

[0006] US Patent No. 6,884,257 US Patent No. 5,961,536 JP Patent Publication No. 2010-527695

[0007] However, with the catheters described in Patent Documents 1 to 3, it is difficult to visually confirm the shape of the proximal end of the balloon portion that expands outside the sheath, even under X-ray fluoroscopy. This can make it difficult to adjust the length of the portion that expands outside the sheath to the length of the lesion or to properly position the portion that expands outside the sheath at the lesion, which can result in damage to normal tissue when treatment is performed on areas other than the lesion.

[0008] The present invention has been made in consideration of the above circumstances, and its purpose is to provide a catheter that can more easily prevent damage to normal tissue when treatment is performed on areas other than the lesion.

[0009] A catheter according to one embodiment of the present invention is as follows: [1] A catheter comprising: a first shaft having a longitudinal direction and a radial direction and having a lumen extending in the longitudinal direction, a tip member connected to a distal end of the first shaft and having a lumen communicating with the lumen of the first shaft, the tip member comprising a tubular sheet-like material containing particles containing a radiopaque material and having a folded portion at a distal portion, a second shaft disposed in the lumen of the first shaft and the lumen of the tip member and moving in the longitudinal direction relative to the first shaft, and a balloon disposed in a distal portion of the second shaft, the balloon having a main body portion that expands and contracts in the radial direction and whose protrusion length from the first shaft can be adjusted depending on the length of a lesion in a patient, wherein at least a part of the folded portion is disposed distal to the distal end of the first shaft, and the inner diameter of the tip member can be expanded by unfolding the folded portion through inflation of the balloon.

[0010] The balloon expands and the folded portions unfold, expanding the inner diameter of the distal end member, allowing the sheet-like material to more easily conform to the shape of the proximal end of the main body portion expanding outside the first shaft. Because the sheet-like material contains particles containing a radiopaque material, the shape of the proximal end of the main body portion expanding outside the first shaft can be more easily visualized under X-ray fluoroscopy. This makes it easier to adjust the length of the main body portion expanding outside the first shaft to the length of the lesion and to appropriately position the main body portion expanding outside the first shaft at the lesion. This makes it easier to prevent damage to normal tissue caused by treatment being performed on areas other than the lesion. Furthermore, because the sheet-like material constituting the distal end member contains particles containing a radiopaque material, the folded shape of the folded portions can be more easily visualized under X-ray fluoroscopy.

[0011] A catheter according to an embodiment of the present invention is preferably any one of the following [2] to [9]. [2] The catheter according to [1], wherein the tip member has, at its proximal portion, a fixed portion whose inner diameter does not expand when the balloon is expanded and which is fixed to the first shaft. [3] The catheter according to [1] or [2], wherein, when the balloon is deflated, the balloon has a plurality of wings, the wings are wound in the circumferential direction of the second shaft, and the folded portion is wound in the circumferential direction of the second shaft, and the winding direction of the folded portion and the wings are opposite to each other in the circumferential direction of the second shaft. [4] The catheter according to any one of [1] to [3], wherein the first shaft has a convex portion protruding radially inward. [5] The catheter according to any one of [1] to [4], wherein, when the balloon is deflated after expansion, the folds of the folded portion that were unfolded by the expansion of the balloon are refolded. [6] The catheter according to any one of [1] to [5], wherein the sheet-like material is made of a material containing a shape-memory resin. [7] The catheter according to any one of [1] to [6], wherein the content of the radiopaque material in the distal portion of the sheet-like material is higher than the content of the radiopaque material in the proximal portion of the sheet-like material. [8] The catheter according to [2], wherein the inner diameter of a portion of the first shaft when the balloon is inflated is larger than the inner diameter of the portion of the first shaft when the balloon is deflated, and the inner diameter of the fixing part when the balloon is inflated is smaller than the inner diameter of the portion of the first shaft when the balloon is inflated. [9] The catheter according to [8], wherein the first shaft has an outer layer and an inner layer located radially inward from the outer layer, and the inner layer is made of a material having a lower hardness than the outer layer.

[0012] The catheter of the present invention can easily prevent damage to normal tissues caused by treatment of areas other than the lesion.

[0013] FIG. 1 is a side view of a catheter according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view (partial side view) of the distal portion of the catheter shown in FIG. 1. FIG. 3 is a cross-sectional view (partial side view) of the catheter shown in FIG. 2, showing a state in which a portion of the main body is expanded outside the first shaft. FIG. 4 is a cross-sectional view (partial side view) of a modified example of the catheter shown in FIG. 2. FIG. 5 is a cross-sectional view (partial side view) of the catheter shown in FIG. 4, showing a state in which a portion of the main body is expanded outside the first shaft. FIG. 6 is a cross-sectional view (partial side view) of a modified example of the catheter shown in FIG. 3. FIG. 7 is a cross-sectional end view of a balloon and a sheet-like material cut in a direction perpendicular to the longitudinal direction of the first shaft. FIG. 8 is a side view of a modified example of a tip member.

[0014] 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.

[0015] A catheter according to one embodiment of the present invention comprises a first shaft having a longitudinal direction and a radial direction and a lumen extending in the longitudinal direction; a tip member connected to the distal end of the first shaft and having a lumen communicating with the lumen of the first shaft, the tip member comprising a sheet-like material containing particles containing an X-ray opaque substance and having a folded portion at its distal end and formed into a cylindrical shape; a second shaft disposed in the lumen of the first shaft and the lumen of the tip member and moving in the longitudinal direction of the first shaft relative to the first shaft; and a balloon disposed in the distal portion of the second shaft, having a main body portion that expands and contracts in the radial direction of the first shaft and whose protrusion length from the first shaft can be adjusted depending on the length of the lesion in the patient. The catheter is characterized in that at least a part of the folded portion is disposed distal to the distal end of the first shaft, and the inner diameter of the tip member can be expanded by unfolding the folded portion through inflation of the balloon.

[0016] The overall configuration of a catheter 100 according to an embodiment of the present invention will be described with reference to Figures 1 to 8. The figures show the catheter 100 including a first shaft 10, a tip member 20, a second shaft 50, and a balloon 60. The first shaft 10 has a longitudinal direction x, a radial direction y, and a circumferential direction c.

[0017] Members and parts of the catheter 100 other than the first shaft 10 also have longitudinal, radial, and circumferential directions. The longitudinal, radial, and circumferential directions of members and parts of the catheter 100 other than the first shaft 10 may or may not match the longitudinal direction x, radial direction y, and circumferential direction c of the first shaft 10. For ease of understanding, this specification shows an embodiment in which the longitudinal, radial, and circumferential directions of all members and parts match the longitudinal direction x, radial direction y, and circumferential direction c of the first shaft 10, respectively.

[0018] In this specification, the proximal side refers to the direction toward the user's hand in the longitudinal direction x of the first shaft 10, and the distal side refers to the opposite side of the proximal side, i.e., the direction toward the treatment target. Furthermore, when each member or part is divided into two equal halves in the longitudinal direction x of the first shaft 10, the distal portion of each member or part is referred to as the distal part of each member or part, and the proximal portion of each member or part is referred to as the proximal portion of each member or part. The distal end of each member or part is the end located most distally of each member or part. The proximal end of each member or part is the end located most proximal of each member or part. The end includes the peripheral portion of the end. That is, the distal end refers to the distal end and the peripheral portion of the distal end, and the proximal end refers to the proximal end and the peripheral portion of the proximal end.

[0019] FIG. 1 is a side view of a catheter according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view (partial side view) of the distal portion of the catheter shown in FIG. 1. FIG. 3 is a cross-sectional view (partial side view) of the catheter shown in FIG. 2, showing a state in which a portion of the main body is expanded outside the first shaft. FIG. 4 is a cross-sectional view (partial side view) of a modified version of the catheter shown in FIG. 2. FIG. 5 is a cross-sectional view (partial side view) of the catheter shown in FIG. 4, showing a state in which a portion of the main body is expanded outside the first shaft. FIG. 6 is a cross-sectional view (partial side view) of a modified version of the catheter shown in FIG. 3. More specifically, FIGS. 2 to 6 show a cross section passing through the central axis of the first shaft and parallel to the longitudinal direction of the first shaft. FIG. 7 is a cross-sectional end view of a balloon and a sheet-like material taken in a direction perpendicular to the longitudinal direction of the first shaft. More specifically, FIG. 7 shows a state in which the balloon has begun to expand and the folded portions of the sheet-like material have begun to unfold. FIG. 8 is a side view showing a modified example of the tip member.

[0020] As shown in FIGS. 1 to 8, the catheter 100 includes a first shaft 10, a tip member 20, a second shaft 50, and a balloon 60.

[0021] 2 to 6, the first shaft 10 has a longitudinal direction x and a radial direction y, and has an inner lumen 10a extending in the longitudinal direction x. The first shaft 10 may have an inner surface 10b facing the inner lumen 10a and an outer surface 10c facing the exterior of the first shaft 10. The first shaft 10 also preferably has a distal end 10d and a proximal end.

[0022] 1 to 8, the tip member 20 is connected to the distal end of the first shaft 10 and has a lumen 20a that communicates with the lumen 10a of the first shaft 10. The tip member 20 may have an inner surface 20b that faces the lumen 20a and an outer surface 20c that faces the exterior of the tip member 20. The lumen 20a of the tip member 20 preferably extends in the longitudinal direction x of the first shaft 10. The tip member 20 also preferably has a distal end 20d and a proximal end 20e.

[0023] The tip member 20 is made up of a cylindrically formed sheet-like material 40. The sheet-like material 40 has particles containing an X-ray opaque material.

[0024] The distal portion of the tip member 20 has a folded portion 41. The folded portion 41 may be provided only in the distal portion of the tip member 20, or may be provided in both the distal and proximal portions of the tip member 20.

[0025] As shown in FIGS. 2 to 6, the second shaft 50 is disposed in the lumen 10a of the first shaft 10 and the lumen 20a of the tip member 20, and moves relative to the first shaft 10 in the longitudinal direction x of the first shaft 10.

[0026] 2 to 6 , the balloon 60 is disposed at the distal portion of the second shaft 50 and has a main body 61 that expands and contracts in the radial direction y of the first shaft 10, and the length of the main body 61 protruding from the first shaft 10 can be adjusted depending on the length of the lesion in the patient. More specifically, it is preferable that the length of the main body 61 protruding from the first shaft 10 can be adjusted by moving the second shaft 50 relative to the first shaft 10 in the longitudinal direction x of the first shaft 10.

[0027] 2 to 6 , at least a portion of the folded portion 41 is disposed distal to the distal end 10d of the first shaft 10. The entire folded portion 41 may be disposed distal to the distal end 10d of the first shaft 10. Although not shown, only a portion of the folded portion 41 may be disposed distal to the distal end 10d of the first shaft 10, with the remaining portion of the folded portion 41 being disposed proximal to the distal end 10d of the first shaft 10.

[0028] As shown in Figures 2 to 6, the inner diameter of the tip member 20 can be expanded by unfolding the folded portion 41 due to the expansion of the balloon 60. Figures 2 and 4 show a state in which the balloon 60 is deflated and the folded portion 41 is folded. Figures 3, 5, and 6 show a state in which the balloon 60 is expanded and the folded portion 41 is unfolded. The inner diameter of only a part of the tip member 20 may be expanded, or the inner diameter of the entire tip member 20 may be expanded.

[0029] As shown in FIGS. 2 to 6 , the folded portion 41 unfolds due to the expansion of the balloon 60, expanding the inner diameter of the distal end member 20, which allows the sheet-like material 40 to more easily conform to the shape of the proximal end of the main body portion 61 expanding outside the first shaft 10. Because the sheet-like material 40 contains particles containing a radiopaque material, the shape of the proximal end of the main body portion 61 expanding outside the first shaft 10 can be easily visualized under X-ray fluoroscopy. This makes it easy to adjust the length of the main body portion 61 expanding outside the first shaft 10 to the length of the lesion and to appropriately position the main body portion 61 expanding outside the first shaft 10 at the lesion. This makes it easy to prevent damage to normal tissue caused by treatment being performed on areas other than the lesion. Furthermore, because the sheet-like material 40 constituting the distal end member 20 contains particles containing a radiopaque material, the folded shape of the folded portion 41 can be easily visualized under X-ray fluoroscopy.

[0030] The catheter 100 can be used, for example, by inserting the distal end of the first shaft 10 to the lesion, and then protruding a portion of the main body 61 of the balloon 60 disposed in the lumen 10a of the first shaft 10 and the lumen 20a of the tip member 20 from the first shaft 10. By expanding the balloon 60 while leaving a portion of the main body 61 protruding from the first shaft 10, it becomes easy to adjust the length of the main body 61 expanding outside the first shaft 10 to the length of the lesion. When a guidewire 1 is used, the guidewire 1 is placed in a body cavity, and then the distal end of the first shaft 10 is inserted to the lesion.

[0031] 6 , the first shaft 10 preferably has a protrusion 14 that protrudes inward in the radial direction y of the first shaft 10. With this configuration, when the balloon 60 is inflated with a portion of the main body 61 protruding from the first shaft 10, the protrusion 14 bites into the balloon 60, making it easier to suppress movement of the balloon 60 in the longitudinal direction x of the first shaft 10.

[0032] The first shaft 10 may have only one protrusion 14, but may also have a plurality of protrusions 14.

[0033] Each protrusion 14 may be elongated and extend in the longitudinal direction x of the first shaft 10, but is preferably elongated and extend in the circumferential direction c of the first shaft 10. Each protrusion 14 may be elongated and extend spirally so as to wind around the second shaft 50. Each protrusion 14 may be columnar, polygonal pyramidal, polygonal truncated pyramidal, conical, truncated conical, or hemispherical, and multiple protrusions 14 having these shapes may be scattered.

[0034] The proximal end of the tip member 20 may be connected to the distal end of the first shaft 10. The proximal end 20e of the tip member 20 may be connected to the distal end 10d of the first shaft 10. The proximal end of the tip member 20 may be fixed to the distal end of the first shaft 10. The proximal end 20e of the tip member 20 may be fixed to the distal end 10d of the first shaft 10.

[0035] The tip member 20 may have a tapered portion whose outer diameter decreases toward the distal side when the balloon 60 is deflated, i.e., in its natural state. The tip member 20 may have a straight tube portion whose outer diameter is constant when the balloon 60 is deflated, i.e., in its natural state.

[0036] The tip member 20 may be made of a material including resin and metal.

[0037] As shown in Figures 1 to 6, the tip member 20 preferably has a fixing portion 22 in its proximal portion. The fixing portion 22 is preferably a portion whose inner diameter does not expand due to the expansion of the balloon 60. Furthermore, the fixing portion 22 preferably has a portion that is fixed to the first shaft 10. It is preferable that at least a portion of the fixing portion 22 is fixed to the first shaft 10 in the longitudinal direction x of the first shaft 10. That is, only a portion of the fixing portion 22 may be fixed to the first shaft 10 in the longitudinal direction x of the first shaft 10, or the entire fixing portion 22 may be fixed to the first shaft 10 in the longitudinal direction x of the first shaft 10. Since the inner diameter of the fixing portion 22 does not expand due to the expansion of the balloon 60, it is possible to make the tip member 20 less likely to come off the first shaft 10.

[0038] The inner diameter of the fixing portion 22 may be expandable by expanding the balloon 60, but in this case, it is preferable that the rate of change of the inner diameter at the distal end of the fixing portion 22 before and after the expansion of the balloon 60 is smaller than the rate of change of the inner diameter at the distal end of the sheet-like material 40 before and after the expansion of the balloon 60.

[0039] It is preferable that the proximal end of the fixing portion 22 is fixed to the distal end of the first shaft 10. The proximal end of the fixing portion 22 may be fixed to the distal end 10d of the first shaft 10. The distal end of the first shaft 10 may be inserted into the inner cavity of the fixing portion 22, and the inner surface of the fixing portion 22 may be fixed to the outer surface 10c of the first shaft 10. The fixing portion 22 may be inserted into the inner cavity 10a of the first shaft 10, and the inner surface 10b of the first shaft 10 and the outer surface of the fixing portion 22 may be fixed to each other.

[0040] The length of the portion of the tip member 20 in the longitudinal direction x of the first shaft 10 whose inner diameter can be expanded by expanding the balloon 60 is preferably longer than the length of the portion of the tip member 20 in the longitudinal direction x of the first shaft 10 whose inner diameter does not expand by expanding the balloon 60. Because the length of the portion of the tip member 20 in the longitudinal direction x of the first shaft 10 whose inner diameter can be expanded by expanding the balloon 60 is relatively long, the shape of the proximal end of the main body portion 61 expanding outside the first shaft 10 can be easily visualized.

[0041] The tip member 20 may be composed of a plurality of members or may be composed of a single member. For example, as shown in Fig. 3, the tip member 20 may be composed of only a sheet-like material 40. As shown in Figs. 5 and 6, the tip member 20 may be composed of a sheet-like material 40 and a ring-shaped member 42.

[0042] The sheet-like material 40 is preferably made of a material containing a shape-memory resin, such as a norbornene-based polymer, a trans-polyisoprene-based polymer, a styrene-butadiene-based copolymer, a polyurethane-based polymer, a polyester-based polymer, a polyolefin-based polymer, or an acrylic-based polymer.

[0043] A cylindrical sheet-like material 40 can be formed by rolling the sheet-like material. The sheet-like material may be formed into a cylindrical shape and then folded to form a sheet-like material 40 having a folded portion 41, or the sheet-like material may be formed into a cylindrical shape and then folded to form a sheet-like material 40 having a folded portion 41. A seamless cylindrical sheet-like material 40 may also be formed by extrusion molding.

[0044] As shown in Figures 2, 4, and 8, when the folding section 41 is folded, the sheet-like material 40 preferably has a portion whose outer diameter decreases toward the distal side. As shown in Figures 3, 5, and 6, when the folding section 41 is unfolded, the sheet-like material 40 preferably has a portion whose outer diameter increases toward the distal side.

[0045] As the material for forming the ring-shaped member 42, the materials exemplified as materials for forming the first shaft 10 and the second shaft 50 described later can be used.

[0046] As shown in Fig. 5, a ring-shaped member 42 may be disposed in the inner cavity of a cylindrically formed sheet-like material 40, and the outer surface of the ring-shaped member 42 and the inner surface of the sheet-like material 40 may be fixed to each other. As shown in Fig. 6, the proximal end of the sheet-like material 40 may be disposed in the inner cavity of the ring-shaped member 42, and the outer surface of the sheet-like material 40 and the ring-shaped member 42 may be fixed to each other.

[0047] It is preferable that the balloon 60 be expanded and then contracted, so that the folds of the foldable portion 41 that were unfolded by the expansion of the balloon 60 are refolded, thereby making it easier to remove the catheter 100 from the body cavity.

[0048] The content of the radiopaque material in the distal portion of the sheet-like material 40 is preferably greater than the content of the radiopaque material in the proximal portion of the sheet-like material 40. This makes it easier to improve the visibility of the shape of the proximal end of the main body portion 61 expanding outside the first shaft 10 under X-ray fluoroscopy.

[0049] Examples of radiopaque materials that can be used include lead, barium, iodine, tungsten, gold, platinum, iridium, stainless steel, titanium, and cobalt-chromium alloys.

[0050] The particles containing a radiopaque substance may be composed entirely of the radiopaque substance, or only a portion of the particles may be composed of the radiopaque substance. The particles containing a radiopaque substance are preferably composed of the radiopaque substance and a dispersant. Examples of dispersants that can be used to form the particles containing the radiopaque substance include resin dispersants such as polyamide resin, polyester resin, polyurethane resin, and polyolefin resin, organic salt dispersants such as magnesium stearate, and inorganic dispersants such as talc. The sheet-like material 40 is preferably formed from a resin matrix containing the above-described radiopaque substances. Examples of resin matrix that can be used include polyamide resin, polyester resin, polyurethane resin, polyolefin resin, vinyl chloride resin, silicone resin, natural rubber, and fluororesin.

[0051] The number of particles containing a radiopaque substance in the distal portion of the sheet-like material 40 is preferably greater than the number of particles containing a radiopaque substance in the proximal portion of the sheet-like material 40. This makes it easier to improve the visibility of the shape of the proximal end of the main body portion 61 expanding outside the first shaft 10 under X-ray fluoroscopy.

[0052] From the viewpoint of improving visibility, as shown in FIG. 8, a radiopaque portion 25 made of a material containing a radiopaque substance may be provided at the distal end of the sheet-like member 40.

[0053] The second shaft 50 can be configured to have an inner cavity extending in the longitudinal direction x of the first shaft 10. As can be seen from Figures 2 to 7, the inner cavity of the second shaft 50 can be used as a passage for inserting the guide wire 1 or the like.

[0054] 2 to 6, the second shaft 50 may have a second inner shaft 51 and a second outer shaft 52. The second outer shaft 52 has an inner lumen and is preferably disposed in the inner lumen 10a of the first shaft 10. The second inner shaft 51 has an inner lumen in which the guide wire 1 is disposed and is preferably disposed in the inner lumen of the second outer shaft 52.

[0055] The second outer shaft 52 is preferably connected to an indeflator that injects a fluid to be supplied inside the balloon 60 .

[0056] The first shaft 10 and the second shaft 50 are preferably flexible, which allows the first shaft 10 and the second shaft 50 to be easily deformed to conform to the shape of the body cavity. In addition, the first shaft 10 and the second shaft 50 are preferably elastic in order to maintain their shape.

[0057] The shape of the first shaft 10 and the second shaft 50 may be, for example, a hollow cylindrical shape, a hollow polygonal prism shape, or the like.

[0058] The first shaft 10 and the second shaft 50 can be, for example, 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 of these, for example, a combination of these connected in the longitudinal direction. Examples of hollow bodies with wires arranged in a predetermined pattern include a tubular body having a mesh structure formed by crossing or weaving wires, and a coil formed by winding wires. The wires may be one or more solid wires or one or more twisted wires. The resin tube can be manufactured, for example, by extrusion molding. When the first shaft 10 and the second shaft 50 are resin tubes, the first shaft 10 and the second shaft 50 can be composed of a single layer or multiple layers. A portion of the first shaft 10 and the second shaft 50 in the longitudinal direction x or circumferential direction c of the first shaft 10 may be composed of a single layer, and the other portion may be composed of multiple layers.

[0059] The first shaft 10 and the second shaft 50 can be made of, for example, synthetic resins such as polyolefin resins (e.g., polyethylene and polypropylene), polyamide resins (e.g., nylon), polyester resins (e.g., PET), aromatic polyether ketone resins (e.g., PEEK), polyether polyamide resins, polyurethane resins, polyimide resins, and fluororesins (e.g., PTFE, PFA, and ETFE), or metals such as stainless steel, carbon steel, and nickel-titanium alloys. These materials may be used alone or in combination of two or more. The first shaft 10 and the second shaft 50 may be made of the same material, or may be made of different materials.

[0060] The outer diameter of the first shaft 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 first shaft 10 can also 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.

[0061] The inner diameter of the first shaft 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 first shaft 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 first shaft 10 is also preferably large enough to allow the second shaft 50 to pass through.

[0062] The balloon 60 is preferably made of a resin. Examples of resins that make up the balloon 60 include polyamide resin, polyester resin, polyurethane resin, polyolefin resin, vinyl chloride resin, silicone resin, and natural rubber. These may be used alone or in combination of two or more. Among these, polyamide resin, polyester resin, and polyurethane resin are preferred. From the viewpoint of thinning and flexibility of the balloon 60, an elastomer resin can be used.

[0063] The balloon 60 may have a distal sleeve portion 64 secured to the second inner shaft 51 and a proximal sleeve portion 65 secured to the second outer shaft 52 .

[0064] 3, 5, and 6, when the balloon 60 is inflated, the main body 61 preferably has a portion 62 protruding from the first shaft 10 and a portion 63 located in the lumen 10a of the first shaft 10. When the balloon 60 is inflated, the portion 62 of the main body 61 protruding from the first shaft 10 preferably has a straight tube portion 62b, a distal tapered portion 62a located distal to the straight tube portion 62b, and a proximal tapered portion 62c located proximal to the straight tube portion 62b. The above-described configuration of the balloon 60 makes it easier for the straight tube portion 62b to come into contact with the lesion.

[0065] 3, it is preferable that the sheet-like material 40 has an abutment portion 24 that abuts against the straight tubular portion 62b when the balloon 60 is inflated. This makes it easier to visualize the proximal end of the straight tubular portion 62b, which is likely to abut against the lesion.

[0066] The contact portion 24 is preferably arranged so as to be parallel to the longitudinal direction of the balloon 60, the longitudinal direction x of the first shaft 10, the longitudinal direction of the second shaft 50, etc. Note that "parallel" as used here includes strict parallelism ±10°.

[0067] When the balloon 60 is deflated, the balloon 60 has multiple wings 66, which are wound around the second shaft 50 in the circumferential direction, and the folded sections 41 are wound around the second shaft 50 in the circumferential direction. It is preferable that the winding direction of the folded sections 41 and the winding direction of the wings 66 are opposite to each other around the second shaft 50. In FIG. 7 , the winding direction of the folded sections 41 coincides with the direction indicated by arrow E, and the winding direction of the wings 66 coincides with the direction indicated by arrow D. With this configuration, when the balloon 60 is inflated, the wound wings 66 unfold in the direction indicated by arrow E. At this time, the wings 66 push the folded sections 41 in the direction indicated by arrow E, which facilitates smooth unfolding of the folded sections 41. It should be noted that an embodiment in which the winding direction of the folded sections 41 and the winding direction of the wings 66 are the same is also acceptable.

[0068] 4 and 5 , it is preferable that the inner diameter of a portion of the first shaft 10 when the balloon 60 is inflated is larger than the inner diameter of the portion of the first shaft 10 when the balloon 60 is deflated, and that the inner diameter of the fixing part 22 when the balloon 60 is inflated is smaller than the inner diameter of the portion of the first shaft 10 when the balloon 60 is inflated. This configuration makes it easier to suppress movement of the balloon 60 in the longitudinal direction x of the first shaft 10 when the balloon 60 is inflated with a portion of the main body part 61 protruding from the first shaft 10. For example, this can be implemented by having the first shaft 10 have an outer layer 15 and an inner layer 16 located inward of the outer layer 15 in the radial direction y of the first shaft 10, and the inner layer 16 being made of a material with a lower hardness than the outer layer 15. The hardness can be measured by measuring the repulsive force during compression, measuring the elastic modulus using a scanning probe microscope (SPM), measuring Rockwell hardness, measuring Shore hardness, etc., but it is preferably measured by measuring Shore hardness.

[0069] The length from the distal end to the proximal end of the catheter 100 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 100 can be, for example, 2500 mm or less, 2450 mm or less, 2400 mm or less, etc.

[0070] 1 , a hub 70 may be connected to the proximal portion of the first shaft 10. The first shaft 10 and the hub 70 may be fixed together. For example, the first shaft 10 and the hub 70 can be fixed together by bonding with an adhesive, welding, screws, or the like.

[0071] FIG. 1 discloses an embodiment in which a guidewire port 13 is formed midway from the distal end to the proximal end of the first shaft 10. The guidewire port 13 is in communication with the lumen 10a of the first shaft 10. FIG. 1 illustrates a so-called rapid exchange catheter 100. The first shaft 10 may have a first distal shaft portion 11 and a first proximal shaft portion 12 located proximally of the first distal shaft portion 11. The first distal shaft portion 11 and the first proximal shaft portion 12 may be separate members, with the proximal end of the member constituting the first distal shaft portion 11 connected to the distal end of the member constituting the first proximal shaft portion 12. Alternatively, the first distal shaft portion 11 and the first proximal shaft portion 12 may be formed from a single member.

[0072] Although not shown, the catheter 100 may be of a so-called over-the-wire type in which a lumen 10a is formed from the distal end to the proximal end of the first shaft 10. When the catheter 100 is of the over-the-wire type, it is preferable that the lumen 10a of the first shaft 10 extend in the longitudinal direction x of the catheter 100 to a position where the hub 70 is located.

[0073] The outer surface 10c of the first shaft 10 may be coated. As shown in Fig. 1, when the catheter 100 is of a rapid exchange type, the outer surface of at least one of the first distal shaft portion 11 and the first proximal shaft portion 12 may be coated, or the outer surfaces of both the first distal shaft portion 11 and the first proximal shaft portion 12 may be coated. When the catheter 100 is of an over-the-wire type, only a portion or the entire outer surface 10c of the first shaft 10 may be coated.

[0074] The coating applied to the outer surface 10c of the first shaft 10 can be a hydrophilic coating or a hydrophobic coating depending on the purpose. The coating can be applied by immersing the first shaft 10 in a hydrophilic or hydrophobic coating agent, by applying a hydrophilic or hydrophobic coating agent to the outer surface 10c of the first shaft 10, or by covering the outer surface 10c of the first shaft 10 with a hydrophilic or hydrophobic coating agent. Drugs or additives may be added to the coating agent.

[0075] Examples of hydrophilic coating agents include hydrophilic polymers such as polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, and methyl vinyl ether-maleic anhydride copolymer, and hydrophilic coating agents composed of combinations of these.

[0076] Examples of hydrophobic coating agents include polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxyalkane (PFA), silicone oil, hydrophobic urethane resin, carbon coat, diamond coat, diamond-like carbon (DLC) coat, ceramic coat, and substances terminated with alkyl groups or perfluoroalkyl groups and having low surface free energy.

[0077] This application claims the benefit of priority based on Japanese Patent Application No. 2024-050050, filed on March 26, 2024. The entire contents of the specification of Japanese Patent Application No. 2024-050050, filed on March 26, 2024, are incorporated herein by reference.

[0078] 1: Guidewire 10: First shaft 10a: Lumen 10b: Inner surface 10c: Outer surface 10d: Distal end 11: First distal shaft portion 12: First proximal shaft portion 13: Guidewire port 14: Convex portion 15: Outer layer 16: Inner layer 20: Tip member 20a: Lumen 20b: Inner surface 20c: Outer surface 20d: Distal end 20e: Proximal end 22: Fixing portion 23: Outer membrane 24: Contact portion 25: Radiopaque portion 40: Sheet-like material 41: Folded portion 42: Ring-shaped member 50: Second shaft 51: Second inner shaft 52: Second outer shaft 60: Balloon 61: Main body portion 62: Portion protruding from first shaft 62a: Distal tapered portion 62b: Straight tube portion 62c: Proximal tapered portion 63: Portion located in the lumen of the first shaft 64: Distal sleeve portion 65: Proximal sleeve portion 66: Wing portion 70: Hub 100: Catheter x: Longitudinal direction of the first shaft y: Radial direction of the first shaft c: Circumferential direction of the first shaft

Claims

1. A catheter comprising: a first shaft having a longitudinal direction and a radial direction and having an inner lumen extending in the longitudinal direction; a tip member connected to the distal end of the first shaft and having an inner lumen communicating with the inner lumen of the first shaft, the tip member being composed of a tubular sheet-like material containing particles containing a radiopaque material and having a folded portion at its distal end; a second shaft disposed in the lumen of the first shaft and the lumen of the tip member and moving in the longitudinal direction relative to the first shaft; and a balloon disposed in the distal portion of the second shaft, having a main body that expands and contracts in the radial direction and whose protrusion length from the first shaft can be adjusted depending on the length of the lesion in the patient, wherein at least a part of the folded portion is disposed distal to the distal end of the first shaft, and the inner diameter of the tip member can be expanded by expanding the balloon and unfolding the folded portion.

2. A catheter according to claim 1, wherein the tip member has a fixed portion at its proximal portion, the inner diameter of which does not expand when the balloon is expanded, and which is fixed to the first shaft.

3. A catheter according to claim 1 or 2, wherein when the balloon is in a deflated state, the balloon has a plurality of wing portions, the wing portions are wound in the circumferential direction of the second shaft, the folded portions are wound in the circumferential direction of the second shaft, and the winding direction of the folded portions and the winding direction of the wing portions are opposite to each other in the circumferential direction of the second shaft.

4. A catheter according to claim 1 or 2, wherein the first shaft has a protrusion protruding radially inward.

5. A catheter according to claim 1 or 2, wherein the folds that were unfolded by the expansion of the balloon are refolded when the balloon is contracted after being expanded.

6. A catheter according to claim 1 or 2, wherein the sheet-like material is made of a material containing a shape-memory resin.

7. A catheter according to claim 1 or 2, wherein the content of the radiopaque material in the distal portion of the sheet-like material is greater than the content of the radiopaque material in the proximal portion of the sheet-like material.

8. A catheter as described in claim 2, wherein the inner diameter of a portion of the first shaft when the balloon is inflated is larger than the inner diameter of said portion of the first shaft when the balloon is inflated, and the inner diameter of the fixing part when the balloon is inflated is smaller than the inner diameter of said portion of the first shaft when the balloon is inflated.

9. A catheter according to claim 8, wherein the first shaft has an outer layer and an inner layer located radially inward from the outer layer, and the inner layer is made of a material having a lower hardness than the outer layer.

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