Catheter

Abstract

To provide a catheter capable of suppressing damage to a non-target tissue and preventing a medicine from falling off.SOLUTION: A catheter includes a first shaft 10, a second shaft 20 disposed in a lumen 10a that moves in a longitudinal direction with respect to the first shaft 10, and a balloon disposed at a distal part of the second shaft 20, and having an expandable part 31 that expands and contracts in a radial direction y, which can adjust a protrusion length of the expandable part 31 from the first shaft 10. The balloon includes a medicine layer 35 disposed on an outer surface of the expandable part 31. The expandable part 31 includes a balloon body part 33 and a wire 32 disposed outward in a radial direction y of the balloon body part 33. In a deflated state, an outermost end 32t of the wire 32 is positioned more outward in the radial direction y than an outermost end 33t of the balloon body part 33. The wire 32 includes a first region present closer on a proximal side than the distal end of the first shaft 10. In the first region, the wire 32 comes in contact with an inner wall of the first shaft 10.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a catheter. [Background technology]

[0002] It is known that stenosis in blood vessels, which are the channels through which blood circulates in the body, can lead to various diseases due to stagnation of blood circulation. In particular, stenosis in the coronary arteries that supply blood to the heart can lead to serious diseases such as angina pectoris and myocardial infarction. One method for treating such vascular stenosis is angioplasty (PTA, PTCA, etc.), which uses a balloon catheter to dilate the stenotic area.

[0003] Known balloon catheters have wires on the surface of the balloon that hold a drug (see, for example, Patent Documents 1 to 3). When such a balloon catheter is used, the wires on the surface of the balloon can penetrate into the narrowed area when the balloon is inflated, thereby dilating the narrowed area, and the drug can be transferred to the inner wall of a body cavity, such as a blood vessel wall, which is expected to prevent the occurrence of lesions such as restenosis. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2008-539959 [Patent Document 2] Special Publication No. 2015-505497 [Patent Document 3] Special Publication No. 2021-521971 Summary of the Invention [Problem to be solved by the invention]

[0005] The length of the lesion to which a catheter with a scoring function provided by a wire-containing portion on the surface of the balloon is applied varies, and it is necessary to select a catheter with a wire-containing portion of a length appropriate for the length of the lesion. In preparation for the lesion being longer than expected, a catheter with a longer wire-containing portion may be selected. However, if the wire-containing portion is longer than the length of the lesion, there is a risk that the wire will come into contact with and damage non-target tissue other than the lesion. Furthermore, if a drug is held in the balloon, there is a risk of the drug falling out.

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a catheter that can suppress damage to non-target tissue and prevent drug loss. [Means for solving the problem]

[0007] A catheter according to an embodiment of the present invention that can solve the above problems is as follows. [1] A first shaft having a longitudinal direction and a radial direction, the first shaft having an inner lumen extending in the longitudinal direction; a second shaft disposed in the lumen and adapted to move in the longitudinal direction relative to the first shaft; a balloon disposed at a distal portion of the second shaft, the balloon having an expandable portion that expands and contracts in the radial direction, and a protruding length of the expandable portion from the first shaft that can be adjusted depending on the length of the lesion of the patient; the balloon has a drug layer disposed on an outer surface of the expandable portion; the expandable portion includes a balloon body and a wire rod disposed radially outward of the balloon body, When the balloon is in a deflated state, the radially outermost end of the wire is located radially outward of the radially outermost end of the balloon body, A catheter in which, when the proximal end of the expandable portion is located proximal to the distal end of the first shaft in the longitudinal direction, the wire has a first region that is located proximal to the distal end of the first shaft, and in the first region, the wire contacts the inner wall of the first shaft with or without the drug layer.

[0008] The balloon has an expandable portion that expands and contracts radially, and the length of the expandable portion protruding from the first shaft can be adjusted depending on the length of the patient's lesion, eliminating the need to change to a different catheter depending on the length of the lesion and improving the efficiency of catheter-based treatment. Furthermore, even if the expandable portion protruding from the first shaft includes a wire, the length of the expandable portion can be adjusted to match the length of the lesion, preventing the wire from contacting and damaging non-target tissue. When adjusting the length of the expandable portion to match the length of the lesion, the expandable portion in its contracted state slides within the lumen of the first shaft. However, the outermost end of the wire is located radially outward from the outermost end of the balloon main body in its contracted state. In the first region, the wire contacts the inner wall of the first shaft with or without a drug layer, preventing the drug layer disposed on the outer surface of the expandable portion from falling off. This allows the wire to be exposed from the first shaft at a length that matches the length of the lesion and applied to the lesion while preventing the drug layer from falling off, enabling catheter-based procedures with improved safety and treatment efficiency.

[0009] Furthermore, the catheter according to the embodiment is preferably any one of the following [2] to

[22] . [2] A catheter as described in [1], wherein the outermost end of the wire is in contact with the inner wall of the first shaft with or without the drug layer interposed therebetween. [3] A catheter as described in [1] or [2], wherein in the first region, the wire is in contact with the inner wall of the first shaft without the drug layer therebetween. [4] A catheter as described in [1] or [2], wherein in the first region, the wire is in contact with the inner wall of the first shaft via the drug layer. [5] The balloon has a straight tube portion, a proximal tapered portion located proximal to the straight tube portion, and a distal tapered portion located distal to the straight tube portion; The catheter according to any one of [1] to [4], wherein the drug layer is disposed on the straight tube portion. [6] The catheter according to any one of [1] to [5], wherein the first shaft has a guide portion on the inner wall of the first shaft that guides the wire. [7] The drug layer is provided from the surface of the wire to the outer surface of the balloon body, A catheter according to any one of [1] to [6], wherein in the longitudinal vertical cross section, the maximum thickness of the drug layer within a region (hereinafter referred to as the "specific region") surrounded by a specific shape obtained by enlarging the cross-sectional edge of the wire rod by two times, centered on the centroid of the cross-sectional edge of the wire rod, is thicker than the maximum thickness of the drug layer on the outer surface of the balloon main body portion outside the specific region. [8] A catheter described in any of [1] to [7], wherein, in a vertical cross section along the longitudinal direction, the maximum thickness of the drug layer in the radially outer half of the specific region is smaller than the maximum thickness of the drug layer in the radially inner half of the specific region. [9] A catheter described in any of [1] to [8], wherein in the longitudinal vertical cross section, the maximum thickness of the drug layer in the radially outer half of the specific region is smaller than the maximum thickness of the drug layer on the outer surface of the balloon body portion other than the specific region.

[10] A catheter according to any one of [1] to [9], wherein, in the longitudinal vertical cross section, the drug layer is present between the outer edge of the cross section of the wire facing the outer surface of the balloon main body and the outer surface of the balloon main body.

[11] A catheter described in any one of [1] to

[10] , which has, in the longitudinal vertical cross section, a portion where the drug layer is not present between the outer edge of the cross section of the wire facing the outer surface of the balloon body and the outer surface of the balloon body.

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

[11] , wherein cracks extending along the extending direction of the wire are formed on the surface of the drug layer.

[13] A catheter as described in

[12] , wherein a protective layer is provided on the outer surface of the drug layer, and the protective layer covers at least a portion of the crack.

[14] The balloon has a straight tube portion, a proximal tapered portion located proximal to the straight tube portion, a distal tapered portion located distal to the straight tube portion, a proximal sleeve portion located proximal to the proximal tapered portion, and a distal sleeve portion located distal to the distal tapered portion, a proximal end of the wire is fixed to the proximal tapered portion and / or the proximal sleeve portion; The catheter according to any one of [1] to

[13] , wherein the distal end of the wire is fixed to the distal tapered portion and / or the distal sleeve portion.

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

[14] , wherein the balloon has wings in a deflated state.

[16] A catheter according to

[15] , wherein the wing portion is arranged overlapping the outer surface of the expandable portion so as not to cover the outermost end of the wire.

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

[16] , wherein the wire is made of resin, metal, or a combination thereof.

[18] A catheter according to any one of [1] to

[17] , wherein the surface free energy of the material constituting the surface of the wire is different from the surface free energy of the material constituting the outer surface of the balloon body.

[19] A catheter according to any one of [1] to

[18] , wherein the surface free energy of the material constituting the surface of the wire is greater than the surface free energy of the material constituting the outer surface of the balloon body.

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

[19] , wherein the first shaft has an inner convex portion on the inner surface of the first shaft that protrudes inward in the radial direction.

[21] The catheter according to

[20] , wherein the wire and the inner convex portion are arranged at different positions in the circumferential direction.

[22] A catheter according to any one of [1] to

[21] , wherein the first shaft has an expansion / contraction section at the distal end of the first shaft, in which the inner diameter of the first shaft expands and contracts in the radial direction. [Effects of the Invention]

[0010] The catheter described above can prevent damage to non-target tissue and prevent the drug from dropping out, thereby enabling catheter-based procedures with improved safety and therapeutic efficiency. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a side view of a catheter according to an embodiment of the present invention. [Figure 2] FIG. 2 is a side view of a second shaft and a balloon of a catheter according to one embodiment of the present invention. [Figure 3] 1 is a longitudinal cross-sectional view of a catheter according to an embodiment of the present invention, showing the expandable section in a contracted state disposed within the first shaft. [Figure 4] 1 is a longitudinal cross-sectional view of a catheter according to an embodiment of the present invention, showing a state in which an expandable section in a contracted state protrudes from a first shaft. [Figure 5] 1 is a longitudinal cross-sectional view of a catheter according to an embodiment of the present invention, showing the expandable section protruding from the first shaft in an expanded state. [Figure 6] FIG. 6 is a cross-sectional view showing a modification of the cross-sectional view shown in FIG. [Figure 7] FIG. 1 is a perspective view of a balloon according to one embodiment of the present invention. [Figure 8] FIG. 10 is a perspective view of a balloon according to another embodiment of the present invention. [Figure 9] FIG. 9 is a cross-sectional end view of the balloon shown in FIG. 8 taken along line IX-IX. [Figure 10] FIG. 4 is a cross-sectional end view of the catheter shown in FIG. 3 taken along line XX. [Figure 11]11 is a cross-sectional end view showing a modification of the cross-sectional end view shown in FIG. 10. FIG. [Figure 12] 11 is a cross-sectional end view showing a further variation of the cross-sectional end view shown in FIG. 10. FIG. [Figure 13] FIG. 10 is an enlarged cross-sectional view of the wire rod and its surroundings in the balloon shown in FIG. [Figure 14] FIG. 10 is an enlarged cross-sectional view showing a modified example of the enlarged cross-sectional view shown in FIG. [Figure 15] 14. FIG. 15 is an enlarged cross-sectional view showing a further modified example of the enlarged cross-sectional view shown in FIG. 9, illustrating an embodiment in which a protective layer provided on the outer surface of the drug layer shown in FIG. 14 covers the cracks. [Figure 16] 11 is a cross-sectional end view showing a further variation of the cross-sectional end view shown in FIG. 10. FIG. [Figure 17] 11 is a cross-sectional end view showing a further variation of the cross-sectional end view shown in FIG. 10. FIG. [Figure 18] FIG. 6 is a cross-sectional view showing a further modification of the cross-sectional view shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described below based on the embodiments, but the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the above and below-described purposes, and all such modifications are included within the technical scope of the present invention. In addition, hatching and component symbols may be omitted in each drawing for convenience. In such cases, reference should be made to the specification or other drawings. The dimensions of various components in the drawings may differ from actual dimensions, as priority is given to helping understand the features of the present invention.

[0013] A catheter according to an embodiment of the present invention comprises a first shaft having a longitudinal and radial direction and an inner lumen extending longitudinally; a second shaft disposed in the inner lumen of the first shaft and moving longitudinally relative to the first shaft; and a balloon disposed in a distal portion of the second shaft, the balloon having an expandable portion that expands and contracts radially, the length of protrusion of the expandable portion from the first shaft being adjustable depending on the length of the lesion in the patient. The balloon has a drug layer disposed on the outer surface of the expandable portion, and the expandable portion has a balloon main body and a wire disposed radially outside the balloon main body, and when the balloon is in a deflated state, the radially outermost end of the wire is located radially outward from the radially outermost end of the balloon main body, and when the proximal end of the expandable portion is located proximal to the distal end of the first shaft, the wire has a first region located proximal to the distal end of the first shaft, and in the first region, the wire is in contact with the inner wall of the first shaft with or without the drug layer interposed therebetween.

[0014] The balloon has an expandable portion that expands and contracts radially, and the length of the expandable portion protruding from the first shaft can be adjusted depending on the length of the patient's lesion, eliminating the need to change to a different catheter depending on the length of the lesion and improving the efficiency of catheter-based treatment. Furthermore, even if the expandable portion protruding from the first shaft includes a wire, the length of the expandable portion can be adjusted to match the length of the lesion, preventing the wire from contacting and damaging non-target tissue. When adjusting the length of the expandable portion to match the length of the lesion, the expandable portion in its contracted state slides within the lumen of the first shaft. However, since the outermost end of the wire is positioned radially outward from the outermost end of the wing of the balloon in its contracted state, the wire can have a contact portion that contacts the inner wall of the first shaft with or without a drug layer. This allows the drug layer located on the outer surface of the expandable portion other than the contact portion to be kept out of contact with the inner wall of the first shaft, preventing the drug layer from falling off the outer surface of the expandable portion. As a result, a wire of a length that matches the length of the lesion can be exposed from the first shaft and applied to the lesion while preventing the drug layer from falling off, making it possible to perform catheter-based procedures with improved safety and therapeutic efficiency.

[0015] A catheter according to an embodiment of the present invention will be described with reference to FIGS. 1 to 18. FIG. 1 is a side view of a catheter according to an embodiment of the present invention. FIG. 2 is a side view of a second shaft and a balloon included in a catheter according to an embodiment of the present invention. FIG. 3 is a longitudinal cross-sectional view of a catheter according to an embodiment of the present invention, showing a state in which an expandable section in a contracted state is disposed within the first shaft. FIG. 4 is a longitudinal cross-sectional view of a catheter according to an embodiment of the present invention, showing a state in which an expandable section in a contracted state protrudes from the first shaft. FIG. 5 is a longitudinal cross-sectional view of a catheter according to an embodiment of the present invention, showing a state in which the expandable section protruding from the first shaft is expanded. FIG. 6 is a cross-sectional view showing a modified first shaft of the catheter shown in FIG. 5. FIG. 7 is a perspective view of a balloon according to an embodiment of the present invention. FIG. 8 is a perspective view of a balloon according to another embodiment of the present invention. FIG. 9 is a cross-sectional end view of the balloon shown in FIG. 8, taken along line IX-IX. FIGS. 7 to 9 show the balloon in an expanded state. Note that the drug layer is omitted from FIGS. 2 to 8. FIG. 10 is a cross-sectional end view taken along line XX of the catheter shown in FIG. 3, showing a configuration in which the wire in the first region directly contacts the inner wall of the first shaft without a drug layer. FIG. 11 is a cross-sectional end view showing a variation of the cross-sectional end view shown in FIG. 10, showing a configuration in which the wire in the first region indirectly contacts the inner wall of the first shaft via a drug layer. FIG. 12 is a cross-sectional end view showing a further variation of the cross-sectional end view shown in FIG. 10, showing a configuration in which the first shaft has a guide portion. FIG. 13 is an enlarged cross-sectional view of the wire and its surroundings of the balloon shown in FIG. 9. FIG. 14 is a cross-sectional view showing a variation of the enlarged cross-sectional view shown in FIG. 13, showing a configuration in which cracks are formed in the drug layer. FIG. 15 is a cross-sectional view showing a further variation of the enlarged cross-sectional view shown in FIG. 13, showing a configuration in which a protective layer provided on the outer surface of the drug layer shown in FIG. 14 covers the cracks. FIG. 16 is a cross-sectional end view showing a further variation of the cross-sectional end view shown in FIG. 10, showing a configuration in which wings are formed on the balloon in a deflated state.Figure 17 is a cross-sectional view showing a further modification of the cross-sectional view shown in Figure 10, in which the first shaft has an inner convex portion. Figure 18 is a cross-sectional view showing a further modification of the cross-sectional view shown in Figure 5. In Figure 18, the drug layer is omitted.

[0016] As shown in FIG. 1, the catheter 100 has a first shaft 10, which has a longitudinal direction x, a radial direction y, and a circumferential direction z. The first shaft 10 preferably has a distal end 10D and a proximal end in the longitudinal direction x. The proximal side of the first shaft 10 refers to the direction toward the user of the catheter 100 in the longitudinal direction x, and the distal side refers to the opposite direction from the proximal side, i.e., the direction toward the treatment target. In FIGS. 1 to 3, the right side of the figure is the proximal side, and the left side of the figure is the distal side. The radial direction y of the first shaft 10 refers to the direction from the centroid of the outer edge of the first shaft 10 toward the outer edge in a direction perpendicular to the longitudinal direction x. The inward direction in the radial direction y of the first shaft 10 refers to the direction toward the centroid of the first shaft 10. The outward direction in the radial direction y refers to the direction extending radially from the centroid of the first shaft 10, opposite to the inward direction. The circumferential direction z of the first shaft 10 refers to a direction along the outer edge of the first shaft 10 in a plane perpendicular to the longitudinal direction x.

[0017] Members other than the first shaft 10, such as the second shaft 20 and the balloon 30, also have longitudinal, radial, and circumferential directions. The longitudinal, radial, and circumferential directions of these members other than the first shaft 10 may or may not match the longitudinal direction x, radial direction y, and circumferential direction z of the first shaft 10. For ease of understanding, this specification will be described assuming that the longitudinal, radial, and circumferential directions of all members match the longitudinal direction x, radial direction y, and circumferential direction z of the first shaft 10, respectively.

[0018] 1 and 3 to 6, the first shaft 10 has an inner cavity 10a extending in the longitudinal direction x. The number of inner cavities 10a that the first shaft 10 has is not particularly limited, and may be one or more, but is preferably one.

[0019] 3 to 6, the first shaft 10 preferably has a distal opening 10d that communicates with the lumen 10a in the longitudinal direction x. A balloon 30 disposed in a distal portion of the second shaft 20, which will be described later, preferably projects and retracts from the distal opening 10d of the first shaft 10.

[0020] FIG. 1 shows a so-called rapid exchange catheter in which the first shaft 10 has a port 10p midway from the distal portion to the proximal portion of the first shaft 10, and the lumen 10a of the first shaft 10 extends from the port 10p to the distal portion of the first shaft 10. Preferably, the second shaft 20 and the balloon 30 are inserted into the lumen 10a of the first shaft 10 through the port 10p. In the case of a rapid exchange catheter, as shown in FIG. 1, the first shaft 10 preferably has a distal first shaft 11 and a proximal first shaft 12, and the distal first shaft 11 and the proximal first shaft 12 may be separate members. When the distal first shaft 11 and the proximal first shaft 12 are separate members, the proximal first shaft 12 may be made of resin or metal.

[0021] Although not shown, the first shaft 10 may be a so-called over-the-wire catheter having a lumen 10a extending from the distal portion to the proximal portion of the first shaft 10. In this case, it is preferable that the first shaft 10 has a proximal opening. It is preferable that the second shaft 20 and the balloon 30 are inserted into the lumen 10a of the first shaft 10 through the proximal opening.

[0022] A handle 15 is preferably connected to the proximal portion of the first shaft 10. This makes it easy to operate the first shaft 10.

[0023] As shown in Figures 1 and 3 to 6, the catheter 100 has a second shaft 20, which is disposed in the lumen 10a of the first shaft 10. The second shaft 20 preferably has a longitudinal direction, a radial direction, and a circumferential direction. Note that, although the present specification will be described taking as an example a case where the longitudinal direction, radial direction, and circumferential direction of the second shaft 20 coincide with the longitudinal direction x, radial direction y, and circumferential direction z of the first shaft 10, these directions may be different from one another.

[0024] As shown in FIGS. 2 to 6, a balloon 30 is disposed at the distal end of the second shaft 20, and the balloon 30 has an expandable portion 31 that expands and contracts in the radial direction y. The second shaft 20 preferably has a flow path 20a for supplying a balloon inflation fluid to the inside of the balloon 30 from the proximal side. For example, the inner cavity of the second shaft 20 can be used as the flow path 20a. The flow path 20a preferably extends in the longitudinal direction of the second shaft 20. The flow path 20a of the second shaft 20 and the inside of the balloon 30 are preferably connected, and a fluid is preferably supplied to the inside of the balloon 30 through the second shaft 20. This allows the expandable portion 31 to be expanded and contracted in the radial direction y using a balloon pressurizer, such as an indeflator. As shown in FIGS. 3 to 6, the expandable portion 31 has a distal end 31D and a proximal end 31P in the longitudinal direction x.

[0025] As can be seen from FIGS. 3 to 5 , the second shaft 20 moves in the longitudinal direction x relative to the first shaft 10. The balloon 30 is also adjustable in the length of the expandable portion 31 protruding from the first shaft 10 depending on the length of the patient's lesion. The position of the second shaft 20 in the longitudinal direction x relative to the first shaft 10 can be adjusted by moving the second shaft 20 in the longitudinal direction x relative to the first shaft 10. When using the catheter 100, the catheter 100 is first inserted into the body and delivered to the lesion. As shown in FIGS. 3 and 4 , with the balloon 30 deflated, the second shaft 20 is moved relative to the first shaft 10 in the longitudinal direction x until the expandable portion 31 is positioned so as to overlap the distal end 10D of the first shaft 10, thereby adjusting the length of the expandable portion 31 protruding from the first shaft 10. Then, the expandable portion 31 of the deflated balloon 30 protrudes from the distal end 10D of the first shaft 10. 5, a fluid is supplied to the inside of the balloon 30 through the second shaft 20 to expand the balloon 30. In this way, by changing the position of the second shaft 20 relative to the first shaft 10 in the longitudinal direction x, the protruding length of the expandable portion 31 from the first shaft 10 can be adjusted. The catheter 100 can be applied to lesions of various sizes. This eliminates the need to prepare multiple catheters with different lengths of the expandable portion 31 in the longitudinal direction x, making treatment using the catheter 100 more efficient.

[0026] In this specification, when the balloon 30, i.e., the expandable portion 31, is expanded at a position where the expandable portion 31 overlaps with the distal end 10D of the first shaft 10 in the longitudinal direction x, the balloon 30 is expanded by supplying a fluid to the second shaft 20 at a pressure of, for example, 1.4 to 4 MPa as the pressure required to expand the balloon 30.

[0027] As shown in FIGS. 2 to 6, the second shaft 20 preferably includes a distal second shaft 21 and a proximal second shaft 22, and the distal second shaft 21 is preferably configured from an inner shaft 21A and an outer shaft 21B. The inner shaft 21A is preferably disposed within the lumen of the outer shaft 21B. The inner shaft 21A can function as a passageway for a guidewire GW that guides the progression of the second shaft 20. The space between the inner shaft 21A and the outer shaft 21B can function as a flow path 20a for a balloon inflation fluid. When the second shaft 20 includes the inner shaft 21A and the outer shaft 21B, the inner shaft 21A can extend from the distal end of the outer shaft 21B and penetrate the outer shaft 21B distally of the balloon 30, with the distal side of the balloon 30 joined to the inner shaft 21A and the proximal side of the balloon 30 joined to the outer shaft 21B.

[0028] 2, a hub 25 is preferably provided on the proximal side of the second shaft 20. The hub 25 preferably has a fluid injection section 26 that communicates with the flow path 20a of the second shaft 20. The balloon 30, the second shaft 20, and the hub 25 can be joined together using a conventional joining means such as adhesive or thermal welding.

[0029] As shown in Fig. 2, a tip member 28 is preferably provided at the distal end of the second shaft 20. The tip member 28 may be provided as a separate member from the inner shaft 21A and located distal to the distal end of the inner shaft 21A, or the inner shaft 21A may extend distal to the distal end of the balloon 30, so that the distal end of the inner shaft 21A functions as the tip member 28. The tip member 28 may have a through-hole extending in the longitudinal direction x. Note that the tip member 28 is omitted from the drawings other than Fig. 2.

[0030] FIG. 2 shows a so-called rapid exchange type balloon catheter in which the second shaft 20 has a guidewire port 23 midway from the distal portion to the proximal portion of the second shaft 20, and a guidewire insertion passage from the guidewire port 23 to the distal portion of the second shaft 20. In the case of a rapid exchange type, the second shaft 20 preferably has a distal second shaft 21 and a proximal second shaft 22, and the distal second shaft 21 and the proximal second shaft 22 may be separate members. When the distal second shaft 21 and the proximal second shaft 22 are separate members, the proximal second shaft 22 may be made of resin or metal. In FIGS. 3 to 6, the distal second shaft 21 of the second shaft 20 has an inner shaft 21A and an outer shaft 21B. In this case, it is preferable that the proximal end of the inner shaft 21A is connected to the guidewire port 23 and the distal end of the inner shaft 21A extends to the distal portion of the second shaft 20, thereby providing a guidewire insertion passage extending from the guidewire port 23 to the distal portion of the second shaft 20.

[0031] Although not shown, the second shaft 20 in which the balloon 30 is disposed may be a so-called over-the-wire catheter. It is preferable that the inner shaft 21A of the second shaft 20 extends from the distal to the proximal portion of the second shaft 20, and that a guidewire insertion passage is disposed from the distal to the proximal side of the second shaft 20. In this case, it is preferable that the balloon inflation fluid flow path 20a and the guidewire insertion passage provided in the second shaft 20 extend to a hub, and that the hub has a fluid injection portion communicating with the balloon inflation fluid flow path 20a and a treatment portion communicating with the guidewire insertion passage. The hub may have a bifurcated structure, with the fluid injection portion provided on one side and the treatment portion provided on the other side.

[0032] The handle 15 and / or the hub 25 can be made of one or more members. These preferably have a shape that is easy for the user to grip. The handle 15 and / or the hub 25 can be made of synthetic resins, such as polyolefin resins such as polyethylene and polypropylene, polyamide resins such as nylon, polyester resins such as PET, aromatic polyether ketone resins such as PEEK, polyether polyamide resins, polyurethane resins, polyimide resins, fluorine-based resins such as PTFE, PFA, and ETFE, polyvinyl chloride resins, carbonate resins, and styrene resins.

[0033] The first shaft 10 and / or the second shaft 20 are preferably flexible so that the catheter 100 can deform to fit the shape of the body cavity. In order to maintain their shape, the first shaft 10 and / or the second shaft 20 are preferably elastic.

[0034] The material constituting the first shaft 10 and / or the second shaft 20 is preferably a resin, a metal, or a combination of a resin and a metal. The use of a resin makes it easier to impart flexibility and elasticity to the shaft. The use of a metal also improves the ease of insertion of the catheter 100 into a body cavity such as a blood vessel. When a metal and a resin are combined, for example, a cylindrical body made of a resin may be combined with a reinforcing material such as a wire made of the metal.

[0035] Examples of resins constituting the first shaft 10 and / or the second shaft 20 include polyamide-based resins such as polyamide and polyamide elastomer, polyester-based resins such as polyethylene terephthalate and polyester elastomer, polyurethane-based resins such as polyurethane and polyurethane elastomer, polyolefin-based resins such as polyethylene, polypropylene, and ethylene-propylene copolymer, polyphenylene sulfide-based resins, polystyrene-based resins, fluorine-based resins, vinyl chloride-based resins, silicone-based resins, natural rubber, synthetic rubber, and polyimide. These may be used alone or in combination of two or more. Examples of polyamides include nylon 12 and nylon 11. Examples of polyamide elastomers include polyether ester amide elastomer and polyamide ether elastomer.

[0036] Examples of metals that can be used to form the first shaft 10 and / or the second shaft 20 include stainless steel such as SUS304 and SUS316, platinum, nickel, cobalt, chromium, titanium, tungsten, gold, nickel-titanium alloys, cobalt-chromium alloys, or combinations thereof.

[0037] The first shaft 10 and / or the second shaft 20 can be made up of one or more members. Examples of the first shaft 10 and / or the second shaft 20 include a resin tube; a metal tube; a hollow body formed by arranging wires in a predetermined pattern; a hollow body with a resin coating on at least one of the inner and outer surfaces; or a combination of these, for example, a combination of these connected in the longitudinal direction x. The resin tube can be manufactured by extrusion molding, for example. Examples of hollow bodies in which wires are arranged in a predetermined pattern include a cylindrical body having a mesh structure formed by simply crossing or weaving wires, and a coil formed by winding wires. The wires are one or more single wires. The mesh structure may be a single or multiple stranded wire. There are no particular limitations on the type of mesh structure, nor on the number of turns or density of the coil. The mesh structure or coil may be formed at a constant density throughout the entire longitudinal direction x of the first shaft 10 and / or the second shaft 20, or may be formed so that the density varies depending on the position in the longitudinal direction x. To increase the flexibility of the metal tube, cuts or grooves may be formed on the outer surface of the metal tube. The shapes of the cuts or grooves may be linear, arc-shaped, annular, spiral, or a combination thereof. The inner shaft 21A and outer shaft 21B preferably included in the second shaft 20 may have any of the above structures. The inner shaft 21A and outer shaft 21B may have the same structure or different structures.

[0038] As shown in FIGS. 3 to 5, the first shaft 10 may be composed of a single layer. Alternatively, as shown in FIG. 6, the first shaft 10 may have an outer layer 10B and an inner layer 10A located inward of the outer layer 10B in the radial direction y. Constructing the first shaft 10 in this manner with multiple layers facilitates designing the first shaft 10 to have a desired function. The inner layer 10A is disposed more inward than the outer layer 10B in the radial direction y. The outer layer 10B may be disposed outermost in the radial direction y. The inner layer 10A may be disposed innermost in the radial direction y. As shown in FIG. 6, the outer layer 10B and the inner layer 10A may be in contact with each other in the radial direction y. One or more layers may be disposed between the outer layer 10B and the inner layer 10A in the radial direction y. The materials constituting the outer layer 10B and the inner layer 10A may be the same type, but are preferably different types.

[0039] Examples of methods for manufacturing the first shaft 10 having an outer layer 10B and an inner layer 10A include a method of co-extrusion molding in which the material constituting the outer layer 10B and the material constituting the inner layer 10A are extruded simultaneously, and a method of manufacturing a tubular member that will become the inner layer 10A and then forming the outer layer 10B on the outer surface of the inner layer 10A by coating or the like.

[0040] The hardness of the outer layer 10B and the inner layer 10A may be the same or different. The hardness of the outer layer 10B and the inner layer 10A can be determined, for example, by measuring the repulsive force when the first shaft 10 is compressed in the radial direction y, by measuring the elastic modulus using a scanning probe microscope (SPM), by measuring Rockwell hardness, by measuring Shore hardness, or the like.

[0041] The inner layer 10A is preferably made of a material with a lower hardness than the outer layer 10B, and more preferably, the inner layer 10A is made of a material with a lower Shore D hardness than the outer layer 10B. Shore D hardness is measured based on ISO 868:2003, a plastics durometer hardness test method. The low hardness of the material making up the inner layer 10A allows the flexibility of the inner layer 10A to absorb the stress that the first shaft 10 receives from the balloon 30 when the expandable portion 31 of the balloon 30 is expanded, thereby making it easier to prevent the balloon 30 from shifting relative to the first shaft 10 when the expandable portion 31 of the balloon 30 is expanded. Furthermore, the outer layer 10B can function as a reinforcing portion, thereby preventing the first shaft 10 from collapsing (flattening) in the radial direction y when inserted into the body, thereby ensuring the slidability of the second shaft 20 disposed within the first shaft 10.

[0042] The Shore D hardness of the inner layer 10A is preferably 9 / 10 or less, preferably 8 / 10 or less, preferably 7 / 10 or less, preferably 6 / 10 or less, and may be 3 / 10 or more, 4 / 10 or more, or 5 / 10 or more of the Shore D hardness of the outer layer 10B. Setting the Shore D hardnesses of the outer layer 10B and the inner layer 10A in this manner makes it easier to achieve the effect of the flexibility of the inner layer 10A absorbing the stress that the first shaft 10 receives from the balloon 30 when the expandable portion 31 of the balloon 30 is expanded.

[0043] The constituent materials of the outer layer 10B and the inner layer 10A can be the same as those described for the resins constituting the first shaft 10 and / or the second shaft 20, but elastomer resins such as polyamide elastomer, polyester elastomer, polyurethane elastomer, etc. are particularly suitable for use as the constituent material of the inner layer 10A.

[0044] 7 and 8, the balloon 30 has a longitudinal direction x, a radial direction y, and a circumferential direction z, and is formed in a cylindrical shape with openings on the proximal and distal sides. The radial direction y of the balloon 30 is a direction perpendicular to the longitudinal direction x, extending radially from the center of the balloon 30. The circumferential direction z of the balloon 30 is a direction along the outer periphery of the balloon 30 in a cross section perpendicular to the longitudinal direction x of the balloon 30. Note that, in this specification, the longitudinal direction x, radial direction y, and circumferential direction z of the balloon 30 will be described as coinciding with the longitudinal direction x, radial direction y, and circumferential direction z of the first shaft 10, but these directions may be different from each other.

[0045] As shown in Figures 7 and 8, the balloon 30 preferably has a straight tube section 30C, a proximal tapered section 30D located proximal to the straight tube section 30C, a distal tapered section 30B located distal to the straight tube section 30C, a proximal sleeve section 30E located proximal to the proximal tapered section 30D, and a distal sleeve section 30A located distal to the distal tapered section 30B. That is, the expandable section 31 is preferably composed of the straight tube section 30C, the proximal tapered section 30D, and the distal tapered section 30B. The straight tube section 30C is formed in a substantially cylindrical shape extending in the longitudinal direction x, and has the largest length (outer diameter) in the radial direction y of the balloon 30. The proximal tapered section 30D is located proximal to the straight tube section 30C and connects to the proximal end of the straight tube section 30C. The proximal tapered section 30D is preferably formed so that its outer diameter decreases with increasing distance from the straight pipe section 30C. The distal tapered section 30B is located distal to the straight pipe section 30C and connects to the distal end of the straight pipe section 30C. The distal tapered section 30B is preferably formed so that its outer diameter decreases with increasing distance from the straight pipe section 30C. The distal sleeve section 30A is located distal to the distal tapered section 30B and connects to the distal end of the distal tapered section 30B. The distal sleeve section 30A is preferably formed in a substantially cylindrical shape. The proximal sleeve section 30E is located proximal to the proximal tapered section 30D and connects to the proximal end of the proximal tapered section 30D. The proximal sleeve section 30E is preferably formed in a substantially cylindrical shape.

[0046] 3 to 8, in the distal portion of the second shaft 20, it is preferable that the inner shaft 21A extends distally from the distal end of the outer shaft 21B, and that the inner shaft 21A extends through the interior space of the balloon 30 from the proximal sleeve portion 30E to the distal sleeve portion 30A. It is also preferable that the outer surface of the inner shaft 21A is joined to the inner surface of the distal sleeve portion 30A of the balloon 30, and that the outer surface of the outer shaft 21B is joined to the inner surface of the proximal sleeve portion 30E of the balloon 30. By configuring the distal portion of the second shaft 20 in this manner, it is possible to supply balloon inflation fluid to the interior space of the balloon 30 through the space between the inner shaft 21A and the outer shaft 21B.

[0047] The size of the balloon 30 is not particularly limited, but for example, the length of the straight pipe portion 30C in the longitudinal direction x can be in the range of 4 mm to 400 mm, and the outer diameter of the straight pipe portion 30C can be in the range of 1 mm to 30 mm.

[0048] The balloon 30 is preferably made of a resin, more preferably a thermoplastic resin. This facilitates the manufacturing of the balloon 30 by molding. Examples of resins that can be used for the balloon 30 include polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer; polyester resins such as polyethylene terephthalate and polyester elastomer; polyurethane resins such as polyurethane and polyurethane elastomer; polyphenylene sulfide resins, polyamide resins such as polyamide and polyamide elastomer; fluorine-based resins; silicone resins; and natural rubbers such as latex rubber. These resins may be used alone or in combination. Among these, polyamide resins, polyester resins, and polyurethane resins are preferred. Elastomer resins are particularly preferred in terms of the thinness and flexibility of the balloon 30. For example, among polyamide resins, nylon 12 and nylon 11 are preferred materials for the balloon 30. Nylon 12 is preferred because it can be easily molded during blow molding. Furthermore, polyamide elastomers such as polyether ester amide elastomers and polyamide ether elastomers are preferably used from the viewpoints of thinning and flexibility of the balloon 30. Among these, polyether ester amide elastomers are preferably used from the viewpoints of high yield strength and good dimensional stability of the balloon 30.

[0049] As shown in Figures 2 to 9, the expandable portion 31 of the balloon 30 includes a balloon body 33 and a wire rod 32 disposed on the outside of the balloon body 33 in the radial direction y. The wire rod 32 in the expandable portion 31 provides the balloon 30 with a scoring function. When the balloon 30 is expanded at a stenotic portion of a blood vessel, the wire rod 32 penetrates the calcified stenotic portion, creating a crack in the stenotic portion. This allows the stenotic portion to be expanded while suppressing dissection of the vascular intima. The wire rod 32 also partially suppresses the expansion of the balloon 30. This allows the portion of the balloon 30 where expansion is suppressed by the wire rod 32 to serve as the starting point for fracture of the drug layer 35 disposed on the outer surface of the balloon 30 (described later). The wire rod 32 also contributes to increasing the strength of the balloon 30 and suppressing overexpansion when pressurized. Furthermore, when adjusting the protruding length of the expandable portion 31 from the first shaft 10 by moving the second shaft 20 in the longitudinal direction x relative to the first shaft 10, the wire 32 can also function as a stopper to prevent the second shaft 20 from moving unnecessarily relative to the first shaft 10.

[0050] The balloon 30 can also be used to treat stenosis or lesions in body cavities other than blood vessels.

[0051] 7 and 8, the wire 32 is preferably disposed on the radially outer side of the balloon main body 33 in at least the expandable portion 31. In particular, the wire 32 is more preferably disposed on the radially outer side of the balloon main body 33 in the straight tube portion 30C. This makes it easier for the wire 32 to penetrate deeply into the stenosis when the balloon 30 is expanded at a stenosis in a blood vessel, thereby improving the scoring function of the wire 32.

[0052] It is preferable that at least a portion of the wire 32 arranged on the radially outward side of the balloon body 33 is not fixed to the balloon body 33 in the straight tube section 30C. The wire 32 may also be arranged on the radially outward side of the balloon body 33 in the proximal tapered section 30D and / or the distal tapered section 30B, or may also be arranged on the radially outward side of the balloon body 33 in the proximal sleeve section 30E and / or the distal sleeve section 30A.

[0053] Only one wire 32 may be provided on the outer side of the balloon body 33 in the radial direction y, or two or more wires 32 may be provided. To maximize the effect of the wires 32, it is preferable to provide two or more wires 32, more preferably three or more, and it is preferable to provide ten or fewer wires 32, and more preferably eight or fewer wires.

[0054] On the outer surface of the balloon body 33, the wire 32 is oriented in the longitudinal direction x as shown in FIG. 8, or may extend parallel to the longitudinal direction x, or may extend parallel to the circumferential direction z, although this is not shown in the drawings, or may have a plurality of different extending directions. When the wires 32 extend obliquely to the longitudinal direction x of the balloon 30, the wires 32 preferably extend spirally in the longitudinal direction x on the outer surface of the balloon body 33.

[0055] 9 to 12, the balloon 30 may have a configuration in which a plurality of wires 32 are arranged on the outer surface of the balloon main body 33 in a cross section perpendicular to the longitudinal direction x. Such configurations include a configuration in which the wires 32 extend obliquely with respect to the longitudinal direction x as shown in FIG. 7, or a configuration in which the wires 32 extend parallel to the longitudinal direction x as shown in FIG. 8. In a cross section perpendicular to the longitudinal direction x, the number of wires 32 located outside the balloon main body 33 in the radial direction y may be three as shown in FIG. 9, or four as shown in FIG. 10, and may be, for example, 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, or 20 or less, 18 or less, 16 or less, 12 or less, or 10 or less.

[0056] The wire 32 can be made of, for example, a resin. Examples of resins that can be used to make the wire 32 include polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer; polyester resins such as polyethylene terephthalate; polyamide resins such as nylon; aromatic polyether ketone resins such as PEEK; polyurethane resins; polyether polyamide resins; polyimide resins; polyamide imide resins; fluorine-based resins such as PTFE, PFA, and ETFE; polyvinyl chloride resins; and silicone resins. These resins may be used alone or in combination. The wire 32 may be made of the same resin as the balloon body 33, or a different resin.

[0057] The wire 32 may be made of metal, or may be made of a combination of metal and resin. Examples of metals that make up the wire 32 include stainless steel such as SUS304 and SUS316, carbon steel, platinum, nickel, cobalt, chromium, titanium, tungsten, gold, nickel-titanium alloys, cobalt-chromium alloys, and tungsten alloys. These may be used alone or in combination of two or more.

[0058] In balloon 30, it is preferable that the surface free energy E1 of the material constituting the surface of wire 32 differs from the surface free energy E2 of the material constituting the outer surface of balloon main body 33. Surface free energy affects wettability and affinity with liquid; the higher the surface free energy, the better the affinity with liquid, and the lower the surface free energy, the more likely the balloon is to repel liquid. Drug layer 35, described below, can be formed, for example, by coating the surface of balloon 30 with a drug solution and drying it. In this case, by appropriately setting the surface free energy E1 of the material constituting the surface of wire 32 and the surface free energy E2 of the material constituting the outer surface of balloon main body 33, drug layer 35 can be selectively provided at desired locations on the surface of balloon 30.

[0059] The surface free energy E1 of the material constituting the surface of the wire 32 and the surface free energy E2 of the material constituting the outer surface of the balloon body 33 can be determined by measuring the contact angle of a droplet of each material in the gas phase or the contact angle of an air bubble in the liquid phase. The contact angle can be measured using a commercially available contact angle meter, and the surface free energy can be calculated from the contact angle measurement results.

[0060] The surface free energy E1 of the material constituting the surface of wire 32 is preferably greater than the surface free energy E2 of the material constituting the outer surface of balloon body 33. By setting the surface free energies of the materials constituting the surface of wire 32 and the outer surface of balloon body 33 in this way, the drug solution becomes more easily intimately attached to the surface of wire 32, making it easier to form a thicker drug layer 35 around wire 32.

[0061] The surface free energy E2 of the material constituting the outer surface of the balloon main body 33 is preferably, for example, 30 dyne / cm or more and 60 dyne / cm or less. The surface free energy E2 is more preferably 35 dyne / cm or more, even more preferably 40 dyne / cm or more, and even more preferably 55 dyne / cm or less. If the surface free energy E2 is within this range, when a chemical solution is applied to the outer surface of the balloon main body 33, the chemical solution is likely to remain sufficiently on the outer surface of the balloon main body 33.

[0062] The surface free energy E1 of the material constituting the surface of wire 32 is preferably at least five times, more preferably at least eight times, and even more preferably at least ten times, the surface free energy E2 of the material constituting the outer surface of balloon body 33. Setting the surface free energy E1 of the material constituting the surface of wire 32 in this manner makes it easier to form a thicker drug layer 35 around wire 32. There is no particular upper limit to the ratio of the surface free energy E1 to the surface free energy E2, and the surface free energy E1 may be 1,000 times or less, 500 times or less, 100 times or less, or 50 times or less the free energy E2.

[0063] The cross-sectional shape of the wire rod 32 is not particularly limited. For example, the shape of the wire rod 32 in a cross section perpendicular to the extending direction of the wire rod 32 may be circular, elliptical, oval, polygonal, irregular, etc. Polygons include polygons with clear corner vertices and straight sides, as well as rounded polygons with rounded corners and polygons with at least some curved sides. The wire rod 32 may be a solid wire or a stranded wire.

[0064] The maximum length of the wire 32 in the circumferential direction z can be, for example, 1 / 100 or more, 1 / 50 or more, 1 / 20 or more, or 1 / 4 or less, 1 / 5 or less, or 1 / 10 or less of the maximum circumferential length of the expandable portion 31 in the expanded state.

[0065] In a cross section perpendicular to the longitudinal direction x, the maximum length in the radial direction y of the wire 32 can be, for example, 0.2 times or more, 0.4 times or more, 0.7 times or more, or 2 times or less, 1.8 times or less, or 1.5 times or less of the maximum length in the circumferential direction z of the wire 32. This makes it easier for the wire 32 to bite into the stenosis when the balloon 30 is inflated at the stenosis, thereby improving the scoring function of the wire 32. Furthermore, as will be described later, this also makes it easier to form a drug layer 35 on the side surface of the wire 32.

[0066] The wire 32 is preferably provided over at least half of the longitudinal direction x of the expandable portion 31, more preferably over at least two-thirds, and even more preferably over at least three-quarters. This allows cracks to be generated over a wide area of ​​the stricture when the balloon 30 is inflated. The wire 32 is preferably provided in the straight tube portion 30C, but may also be provided in the distal tapered portion 30B and / or the proximal tapered portion 30D or the distal sleeve portion 30A and / or the proximal sleeve portion 30E. In FIGS. 7 and 8, the wire 32 extends from the proximal sleeve portion 30E through the straight tube portion 30C to the distal sleeve portion 30A.

[0067] 4 and 5 , in the deflated and expanded states of the balloon 30, when the expandable portion 31 is positioned to overlap the distal end 10D of the first shaft 10 in the longitudinal direction x, it is preferable that the wire 32 be present from a position distal to the distal end 10D of the first shaft 10 to a position proximal to the distal end 10D of the first shaft 10. In particular, in the deflated and expanded states of the balloon 30, when the expandable portion 31 is positioned to overlap the distal end 10D of the first shaft 10 in the longitudinal direction x, it is preferable that the distal end 32D of the wire 32 be located distal to the distal end 10D of the first shaft 10, and the proximal end 32P of the wire 32 be located proximal to the distal end 10D of the first shaft 10. For example, the distal end 32D of the wire 32 may be arranged in the distal sleeve portion 30A, the distal tapered portion 30B, or any position between the proximal side of the distal end 31D of the expandable portion 31 and the distal side of the distal end 10D of the first shaft 10 in the longitudinal direction x. Furthermore, the proximal end 32P of the wire 32 may be arranged in the proximal sleeve portion 30E, the proximal tapered portion 30D, or any position between the distal side of the proximal end 31P of the expandable portion 31 and the proximal side of the distal end 10D of the first shaft 10. This allows the portion of wire 32 distal to distal end 10D of first shaft 10 to come into contact with the lesion, while the portion of wire 32 proximal to distal end 10D of first shaft 10, i.e., the portion housed in lumen 10a of first shaft 10, does not come into unnecessary contact with the body cavity wall and prevents displacement of second shaft 20 relative to first shaft 10. As a result, contact of wire 32 with the stenosis can be kept to a minimum, preventing damage to non-target tissue.

[0068] Here, when multiple wires 32 are arranged, the distal end 32D of the wire 32 refers to the distal end located most distally among the distal ends of each wire 32, and the proximal end 32P of the wire 32 refers to the proximal end located most proximal among the proximal ends of each wire 32.

[0069] As shown in Figures 7 and 8, the balloon 30 has a straight tube section 30C, a proximal tapered section 30D located proximal to the straight tube section 30C, a distal tapered section 30B located distal to the straight tube section 30C, a proximal sleeve section 30E located proximal to the proximal tapered section 30D, and a distal sleeve section 30A located distal to the distal tapered section 30B, and it is preferable that the proximal end of the wire 32 is fixed to the proximal tapered section 30D and / or the proximal sleeve section 30E, and the distal end of the wire 32 is fixed to the distal tapered section 30B and / or the distal sleeve section 30A.

[0070] The wire 32 and the balloon 30 may be fixed to each other by any method, and the wire 32 and the balloon 30 may be fixed to each other by at least one of brazing (e.g., soldering), welding, melt-bonding, adhesive bonding, and crimping. As shown in Figures 7 and 8, a fixing member 37 may be used to fix the wire 32 and the balloon 30. The fixing member 37 may be, for example, a ring-shaped member or a cylindrical member having a C-shaped cross section perpendicular to the longitudinal direction x.

[0071] Although not shown, the balloon 30 may have an inner convex portion that protrudes inward in the radial direction y on the inner surface of the balloon 30. The inner convex portion may be provided by forming a portion of the balloon body 33 to be thicker.

[0072] As shown in Figures 10 and 11, the balloon 30 has a drug layer 35 disposed on the outer surface of the expandable portion 31. The drug contained in the drug layer 35 is not particularly limited as long as it is a pharmacologically active substance, and examples include medicaments acceptable as medicines such as gene therapy drugs, non-gene therapy drugs, small molecules, and cells. In particular, when the balloon catheter 100 is used for the purpose of suppressing vascular restenosis after angioplasty treatment, anti-restenosis drugs such as antiproliferative agents and immunosuppressants are preferably used as the drug. Specifically, drugs such as paclitaxel, sirolimus (rapamycin), everolimus, and zotarolimus can be used. These drugs may be used alone or in combination.

[0073] In addition to the pharmacologically active substance, drug layer 35 may contain an auxiliary agent for improving the drug's dispersibility, solubility, migration to the vascular wall, and storage stability. Examples of the auxiliary agent include a stabilizer, binder, disintegrant, moisture-proofing agent, preservative, and dissolution aid. Specific examples include lactose, sucrose, maltose, dextrin, xylitol, erythritol, mannitol, ethylenediamine, potassium iodide, urea, polysorbate, dibutylhydroxytoluene, polyethylene glycol, lipid, sodium pyrosulfite, ascorbic acid, tocopherol, benzoic acid, parahydroxybenzoic acid ester, polyacrylic acid, polylactic acid, polyglycolic acid, hyaluronic acid, chitosan, and gelatin.

[0074] As illustrated in FIG. 15 , drug layer 35 may have a protective layer 38 to prevent the drug from eluting into the blood or dropping off during delivery to the stricture site. Preferably, protective layer 38 is included as part of drug layer 35 and constitutes the outermost layer of drug layer 35. That is, protective layer 38 may be disposed on the outer surface of drug layer 35. Protective layer 38 may be composed of a hydrophilic component such as a water-soluble polymer. For example, when balloon 30 is delivered to a body cavity containing a body fluid containing a large amount of lipid-soluble components, such as a bile duct containing bile, if protective layer 38 composed of a hydrophilic component is provided on the outer surface of drug layer 35, dissolution of protective layer 38 upon contact with body fluid is suppressed, and protective layer 38 can perform its protective function for drug layer 35. Examples of hydrophilic components include hydrophilic polymers such as carboxymethyl cellulose, hydroxypropyl cellulose, methyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, alginic acid, pectin, gum arabic, gellan gum, guar gum, xanthan gum, carrageenan, gelatin, polyethylene glycol, hyaluronic acid, and sodium polyacrylate; salts such as potassium chloride and ammonium acetate; amino acids such as glycine and glutamic acid; sugars such as glucose and fructose; and urea. Protective layer 38 may be composed of a hydrophobic component. For example, when balloon 30 is delivered to a body cavity containing a body fluid with a high water content, such as a blood vessel containing blood, providing protective layer 38 composed of a hydrophobic component on the outer surface of drug layer 35 can prevent dissolution of protective layer 38 upon contact with body fluid, allowing protective layer 38 to perform its protective function for drug layer 35. Examples of hydrophobic components include lipid compounds such as lecithin, propylene glycol stearate, cholesterol, and terpenes; hydrocarbon compounds such as petrolatum; hydrophobic (meth)acrylic polymers such as polyethyl acrylate and polymethyl methacrylate; hydrophobic polyester polymers such as polylactic acid and polyglycolic acid; and silicone oil.

[0075] Even when the balloon 30 is delivered to a body cavity containing a body fluid with a high water content, such as a blood vessel containing blood, the protective layer 38 is preferably composed of the aforementioned hydrophilic component, particularly a high-molecular-weight hydrophilic polymer. Using a high-molecular-weight hydrophilic polymer for the protective layer 38 can prevent dissolution of the protective layer 38 due to the water content of the body fluid, making it easier to maintain the protective function of the drug layer 35.

[0076] The protective layer 38 is preferably amorphous, which can enhance the protective function of the protective layer 38. Examples of components of the amorphous protective layer 38 include hydrophilic polymers such as hyaluronic acid and sodium poly(meth)acrylate, hydrophobic polyester polymers such as D,L-polylactic acid and lactic acid-glycolic acid copolymer, and lipid compounds such as lecithin.

[0077] The drug constituting drug layer 35 is preferably crystalline, and it is particularly preferred that the pharmacologically active substance be crystalline. Examples of crystalline pharmacologically active substances include paclitaxel, sirolimus (rapamycin), everolimus, and zotarolimus. It is also preferred that the auxiliary agent or protective agent contained together with the pharmacologically active substance be crystalline. Examples of crystalline auxiliary agents or protective agents include sugar, urea, salts such as potassium iodide, ascorbic acid, polylactic acid, and polyglycolic acid. This increases the brittleness of drug layer 35, making drug layer 35 more likely to peel off from the outer surface of balloon 30 when balloon 30 is inflated. On the other hand, protective layer 38 is preferably amorphous to enhance its protective function.

[0078] The drug layer 35 may be disposed on both the outer surface of the balloon body 33 and the outer surface of the wire 32, or may be disposed over the entire expandable portion 31, i.e., the entire balloon body 33 and the entire wire 32. Alternatively, the drug layer 35 may be disposed over the entire balloon body 33 and part of the wire 32 of the expandable portion 31, or may be disposed over part of the balloon body 33 and part of the wire 32.

[0079] 10 to 12, when the balloon 30 is in a deflated state, the outermost end 32t in the radial direction y of the wire 32 is located further outward in the radial direction y than the outermost end 33t in the radial direction y of the balloon main body 33. The outermost end 32t in the radial direction y of the wire 32 can be defined as the point on a cross section perpendicular to the longitudinal direction x that is farthest from the centroid O of the balloon main body 33 for each wire 32. The outermost end 33t in the radial direction y of the balloon main body 33 can be defined as the point on a cross section perpendicular to the longitudinal direction x that is farthest from the centroid O of the balloon main body 33.

[0080] When multiple wires 32 are arranged in a cross section perpendicular to the longitudinal direction x, it is sufficient that the outermost end 32t of at least one wire 32 is located radially outward in the y direction from the outermost end 33t of the balloon main body 33, and it is preferable that the outermost ends 32t of all wires 32 are located radially outward in the y direction from the outermost end 33t of the balloon main body 33. In this case, the distances from the centroid O of the outermost ends 32t of the wires 32 may be the same or different.

[0081] When the balloon 30 is in a deflated state, the outermost end 32t in the radial direction y of the wire 32 is located radially outward of the outermost end 33t in the radial direction y of the balloon main body 33. This prevents the balloon main body 33 from contacting the wall of the lumen 10a of the first shaft 10 when the balloon 30 is in a deflated state and housed in the lumen 10a of the first shaft 10. This prevents the drug layer 35 disposed on the balloon main body 33 from rubbing against the wall of the lumen 10a and falling off the balloon main body 33. The wall of the lumen 10a refers to the inner wall of the first shaft 10 that forms the lumen 10a.

[0082] The outermost ends 32t of the wires 32 only need to be located radially outward of the outermost ends 33t of the balloon main body 33 when the deflated balloon 30 is located within the lumen 10a of the first shaft 10. That is, in the first region 32A, the outermost ends 32t of the wires 32 only need to be located radially outward of the outermost ends 33t of the balloon main body 33. When the balloon 30 is exposed outside the lumen 10a of the first shaft 10, it is not necessary for the outermost ends 32t of the wires 32 to be located radially outward of the outermost ends 33t of the balloon main body 33, even when the balloon 30 is deflated.

[0083] As shown in FIGS. 3 to 6 , when the proximal end 31P of the expandable section 31 is located proximal to the distal end 10D of the first shaft 10 in the longitudinal direction x, the wire 32 has a first region 32A that is located proximal to the distal end 10D of the first shaft 10, and as shown in FIGS. 10 to 12 , in the first region 32A, the wire 32 is in contact with the inner wall of the first shaft 10, i.e., the wall of the lumen 10a, with or without the drug layer 35 interposed therebetween. That is, in the first region 32A, the wire 32 is in direct or indirect contact with the inner wall of the first shaft 10. Although not shown, if a protective layer 38 is disposed on the outside of the drug layer 35, the wire 32 may be in contact with the inner wall of the first shaft 10, i.e., the wall of the lumen 10a, with the drug layer 35 and the protective layer 38 interposed therebetween in the first region 32A.

[0084] In the first region 32A, the balloon 30 is preferably in a deflated state. At this time, the balloon 30 may have wing portions 34, which will be described later, as shown in FIG. 16, or may be deflated in an irregular shape without wing portions 34, as shown in FIGS. 10 to 12. The balloon 30 preferably deflates so that the inner surface of the balloon main body 33 of the expandable section 31 approaches the outer surface of the second shaft 20. At least a portion of the inner surface of the balloon main body 33 may be in contact with the outer surface of the second shaft 20. The portion of the inner surface of the balloon main body 33 that is in contact may be, for example, the second shaft 21 on the distal side of the second shaft 20. This allows the maximum diameter of the balloon 30 in its deflated state to be reduced.

[0085] The catheter 100 can adjust the protruding length of the expandable portion 31 from the first shaft 10 to match the length of the patient's lesion by moving the second shaft 20 in the longitudinal direction x relative to the first shaft 10, that is, by moving the expandable portion 31 from a state in which the expandable portion 31 is housed in the lumen 10a of the first shaft 10 as shown in Fig. 3 to a position in the longitudinal direction x where the expandable portion 31 overlaps with the distal end 10D of the first shaft 10 as shown in Fig. 4. During this movement, the expandable portion 31 in a contracted state slides in the lumen 10a of the first shaft 10, and there is a risk that the drug layer 35 arranged on the outer surface of the expandable portion 31 will rub against the wall of the lumen 10a of the first shaft 10 and fall off the expandable portion 31. However, in catheter 100, outermost end 32t of wire 32 is located radially outward of outermost end 33t of balloon main body 33 of deflated balloon 30, and in first region 32A where wire 32 is located proximal to distal end 10D of first shaft 10, wire 32 is in contact with the inner wall of first shaft 10, i.e., the wall of lumen 10a, with or without drug layer 35 interposed therebetween, thereby preventing drug layer 35 disposed on a portion other than wire 32 in contact with the inner wall of first shaft 10 from rubbing against the wall of lumen 10a of first shaft 10. This makes it possible to prevent drug layer 35 from falling off from expandable section 31.

[0086] Wire 32 may be in contact with the inner wall of first shaft 10 over the entire range of first region 32A, with or without drug layer 35 interposed therebetween. Alternatively, wire 32 may be in contact with the inner wall of first shaft 10 over at least a portion of first region 32A, with or without drug layer 35 interposed therebetween.

[0087] 10 and 11 , in the first region 32, it is preferable that the balloon body 33 does not contact the inner wall of the first shaft 10 with or without the drug layer 35 interposed therebetween. That is, it is preferable that the balloon body 33 does not contact, directly or indirectly, the inner wall of the first shaft 10. It is more preferable that in the first region 32, the drug layer 35 is formed on the outer surface of the balloon body 33, and the surface of the drug layer 35 does not contact the inner wall of the first shaft 10.

[0088] The first region 32A is the portion of the wire 32 that is located proximal to the distal end 10D of the first shaft 10, and therefore, as shown in Figure 3, when the expandable portion 31 is completely contained in the inner cavity 10a of the first shaft 10, the entire wire 32 formed in the expandable portion 31 contacts the first region 32A.

[0089] As shown in Figure 4, when a portion of the expandable portion 31 protrudes distally from the distal end 10D of the first shaft 10, a portion of the wire 32, i.e., the wire 32 that is proximal to the distal end 10D of the first shaft 10 in the longitudinal direction x, contacts the first region 32A.

[0090] 5, when the expandable portion 31 protruding from the first shaft 10 is expanded, the expandable portion 31 located proximal to the distal end 10D of the first shaft 10 may remain in a contracted state, or may be slightly expanded to a range that fits within the lumen 10a of the first shaft 10. In either case, in the first region 32A, the wire 32 is preferably in contact with the inner wall of the first shaft 10 with or without the drug layer 35 interposed therebetween.

[0091] When expandable section 31 has multiple wires 32, it is preferable that in first region 32A, all of the multiple wires 32 are in direct or indirect contact with the inner wall of first shaft 10. In this case, all of wires 32 may be in contact with the inner wall of first shaft 10 via drug layer 35, all of wires 32 may be in contact with the inner wall of first shaft 10 without drug layer 35, or some of the multiple wires 32 may be in contact with the inner wall of first shaft 10 via drug layer 35 and the rest of the multiple wires 32 may be in contact with the inner wall of first shaft 10 without drug layer 35.

[0092] Alternatively, when the expandable section 31 has multiple wires 32, in the first region 32A, some of the multiple wires 32 may be in direct or indirect contact with the inner wall of the first shaft 10, while the rest of the multiple wires 32 may not be in contact with the inner wall of the first shaft 10. Even in this case, it is preferable that the surface of the drug layer 35 formed on the outer surface of the balloon body 33 is not in contact with the inner wall of the first shaft 10.

[0093] As shown in FIGS. 10 and 11 , the outermost end 32t of the wire 32 preferably contacts the inner wall of the first shaft 10 with or without the drug layer 35 interposed therebetween. The outermost end 32t of the wire 32 is the point at which, in a cross section perpendicular to the longitudinal direction x, the wire 32 is farthest from the centroid O of the balloon main body 33. Although not shown, if a protective layer 38 is disposed on the outside of the drug layer 35, the outermost end 32t of the wire 32 may contact the inner wall of the first shaft 10 with the drug layer 35 and the protective layer 38 interposed therebetween. Having the outermost end 32t directly or indirectly contact the inner wall of the first shaft 10 increases the distance from the balloon main body 33 and the portions of the expandable portion 31 other than the outermost end 32t of the wire 32 to the inner wall of the shaft 10. This makes it easier to prevent the drug layer 35 disposed on the outer surface of the expandable portion 31 from falling off.

[0094] 10 , in first region 32A, wire 32 preferably contacts the inner wall of first shaft 10 without drug layer 35 therebetween. That is, it is preferable that drug layer 35 is not disposed on the portion of wire 32 that contacts the inner wall of first shaft 10, and wire 32 is in direct contact with the inner wall of first shaft 10. This prevents drug layer 35 from falling off from the portion of wire 32 that contacts the inner wall of first shaft 10, thereby preventing loss of drug layer 35 and the adverse effects of such loss. Furthermore, since wire 32 in first region 32A is a portion that contributes to fixation when determining the amount of protrusion of expandable portion 31 from first shaft 10 and fixing it, not disposing drug layer 35 on the portion of wire 32 that contacts the inner wall of first shaft 10 has the effect of strengthening the fixation.

[0095] 11 , in first region 32A, wire 32 may be in contact with the inner wall of first shaft 10 via drug layer 35. That is, drug layer 35 may also be disposed on the portion of wire 32 that is in contact with the inner wall of first shaft 10, and wire 32 may be in indirect contact with the inner wall of first shaft 10. This allows drug layer 35 to be disposed over a wider area, including the portion of wire 32 that is in contact with the inner wall of first shaft 10, making it possible to retain more drug layer 35 in expandable section 31. Although not shown, if protective layer 38 is disposed on the outside of drug layer 35, wire 32 may be in contact with the inner wall of first shaft 10 via drug layer 35 and protective layer 38.

[0096] As shown in Figures 7 and 8, the balloon 30 has a straight tube section 30C, a proximal tapered section 30D located proximal to the straight tube section 30C, and a distal tapered section 30B located distal to the straight tube section 30C, and the drug layer 35 is preferably disposed in the straight tube section 30C. Because the straight tube section 30C is the section formed to have the greatest length in the radial direction y, disposing the drug layer 35 in the straight tube section 30C allows the drug in the drug layer 35 to act efficiently on the lesion. Even if the drug layer 35 is disposed in the straight tube section 30C, because the catheter 100 has the above-described configuration, it is possible to prevent the drug layer 35 from falling off the straight tube section 30C during delivery of the catheter 100 or when adjusting the protruding length of the expandable section 31 from the first shaft 10.

[0097] 12, the first shaft 10 preferably has a guide portion 10G that guides the wire 32 on the inner wall of the first shaft 10. If the first shaft 10 has a guide portion 10G on the inner wall, the guide portion 10G guides the wire 32, allowing the balloon 30 to be positioned in the lumen 10a of the first shaft 10 without shifting and at the intended position in the circumferential direction z.

[0098] When a guide portion 10G is provided on the inner wall of the first shaft 10, in the first region 32A, the wire 32 may be in contact with the guide portion 10G with or without the drug layer 35 interposed therebetween. In this case, the outermost end 32t of the wire 32 may be in contact with the guide portion 10G, or a portion of the wire 32 other than the outermost end 32t may be in contact with the guide portion 10G.

[0099] As shown in FIG. 12, the guide portion 10G may be one or more recesses arranged on the inner surface of the first shaft 10. The wire 32 can be inserted into the recesses to prevent misalignment in the circumferential direction z. The one or more recesses preferably extend in the longitudinal direction x of the first shaft 10. This makes it easier to move the second shaft 20 and the balloon 30 along the extending direction of the recesses, thereby making it easier to slide the second shaft 20 relative to the first shaft 10. The recesses are preferably arranged continuously in the longitudinal direction x. The guide portion 10G may be arranged parallel to the longitudinal direction x, or may have a configuration that is not parallel to the longitudinal direction x, for example, a spiral configuration.

[0100] Alternatively, although not shown, the guide portion 10G may have a rail-like structure that is arranged so as to be convex on the inner surface of the first shaft 10. The rail-like guide portion 10G can guide the wire 32 of the balloon 30 and prevent positional deviation in the circumferential direction z.

[0101] As shown in Figure 13, the drug layer 35 is provided from the surface of the wire 32 to the outer surface of the balloon main body 33, and in a vertical cross section in the longitudinal direction x, it is preferable that the maximum thickness T1 of the drug layer 35 within a region surrounded by a circle 32S (hereinafter referred to as the "specific region 32R") having a center 32C of the circumscribing circle of the cross-sectional outer edge of the wire 32 and twice the radius of the circumscribing circle is thicker than the maximum thickness T2 of the drug layer 35 on the outer surface of the balloon main body 33 other than the specific region 32R.

[0102] In a cross section perpendicular to the longitudinal direction x, a line segment is drawn connecting the centroid O of the balloon body 33 and the outer edge of the drug layer 35. The longest length of the line segment that crosses the drug layer 35 within the specific region 32R is defined as the maximum thickness T1, and the longest length of the line segment that crosses the drug layer 35 outside the specific region 32R is defined as the maximum thickness T2. If the line segment crosses each region at two or more locations, the total length at all locations is defined as each thickness.

[0103] In FIG. 13, circle 32S is depicted by a dashed line, and the line segment connecting centroid O and the outer edge of drug layer 35 is depicted by a dashed line.

[0104] The maximum thickness T1 of drug layer 35 within specific region 32R is, for example, preferably at least 1.2 times, more preferably at least 1.5 times, and even more preferably at least 1.8 times, the maximum thickness T2 of drug layer 35 outside specific region 32R. There is no particular upper limit to the ratio of the maximum thickness T1 of drug layer 35 within specific region 32R to the maximum thickness T2 of drug layer 35 outside specific region 32R, and drug layer 35 may be absent or may be present at a very thin thickness on the outer surface of balloon body 33 outside specific region 32R. For example, the maximum thickness T1 of drug layer 35 within specific region 32R may be 100 times or less, 50 times or less, 30 times or less, 20 times or less, or 10 times or less, the maximum thickness T2 of drug layer 35 on the outer surface of balloon body 33 outside specific region 32R.

[0105] It is anticipated that cracks 35g, which will be described later, may occur on the surface of drug layer 35. In such a case, the thickness of drug layer 35 may be determined based on the area excluding the area where cracks 35g have occurred.

[0106] With the above configuration, when the balloon 30 is expanded at the narrowed portion, the wire 32 penetrates into the narrowed portion, effectively expanding the narrowed portion, and the drug layer 35 is present in a thick layer within the specific region 32R, i.e., the drug layer 35 is present in a thick layer near the wire 32, allowing the drug to be efficiently transferred from the inner surface of the blood vessel wall to the interior of the blood vessel wall at the expanded narrowed portion.

[0107] As shown in Figure 14, it is preferable that cracks 35g extending along the extension direction of wire 32 are formed on the surface of drug layer 35. Figure 14 shows an example of a configuration in which cracks 35g are formed in drug layer 35 in the cross-sectional view of balloon 30 shown in Figure 13. By forming cracks 35g on the surface of drug layer 35, when drug layer 35 comes into contact with the inner surface of the blood vessel wall when balloon 30 is expanded at the stenosis site, drug layer 35, which is provided from the surface of wire 32 to the outer surface of balloon body 33, is likely to peel off from the surface of balloon 30 starting from cracks 35g, making it easier for drug layer 35 to migrate from the surface of balloon 30 toward the blood vessel wall.

[0108] When viewed from outside the balloon 30, the cracks 35g may be formed to extend parallel to the extension direction of the wire 32, or at least a portion of the cracks 35g may be formed to extend obliquely to the extension direction of the wire 32. The cracks 35g may be formed to extend entirely along the extension direction of the wire 32. The cracks 35g may be formed to extend continuously along the wire 32, or may be formed to extend intermittently. Furthermore, multiple cracks 35g extending along the wire 32 may be arranged partially side by side with each other.

[0109] Cracks 35g may be formed so as to extend from the surface of drug layer 35 to the surface of wire 32 or the outer surface of balloon body 33, or may be formed so as to extend from the surface of drug layer 35 to the interior of drug layer 35 as an end point. Cracks 35g on the surface of drug layer 35 are preferably formed within specific region 32R. More preferably, cracks 35g are entirely contained within specific region 32R. By forming cracks 35g in this manner, when balloon 30 is expanded at the stenosis site, drug layer 35 provided on the surface of wire 32 does not penetrate cracks 35g. The adhesive layer 34 is likely to peel off from the surface of the balloon 30 starting from this point.

[0110] As shown in FIG. 15, a protective layer 38 may be provided on the outer surface of the drug layer 35, and the protective layer 38 may cover at least a portion of the crack 35g. FIG. 15 shows a configuration example in which the protective layer 38 is provided on the outer surface of the drug layer 35 so as to cover the crack 35g in the cross-sectional view of the balloon 30 shown in FIG. 14. By providing the protective layer 38 on the outer surface of the drug layer 35 so as to cover at least a portion of the crack 35g, it is possible to prevent bodily fluids from entering the crack 35g during delivery of the catheter 100 to the stenotic site, which could cause the drug layer 35 to fall off or the drug to elute from the drug layer 35. The protective layer 38 is preferably provided on the outer surface of the drug layer 35 so as to cover the entire crack 35g. It is more preferable that the protective layer 38 be provided so as to penetrate into the crack 35g and fill at least a portion of the crack 35g.

[0111] As shown in Figure 13, in a vertical cross section in the longitudinal direction x, it is preferable that the maximum thickness T3 of the drug layer 35 in the outer half 32R1 of the specific region 32R in the radial direction y is smaller than the maximum thickness T4 of the drug layer 35 in the inner half 32R2 of the specific region 32R in the radial direction y.

[0112] In a cross section perpendicular to the longitudinal direction x, a line segment is drawn connecting the centroid O of the balloon main body 33 and the outer edge of the drug layer 35, and the longest length that the line segment crosses the drug layer 35 within the outer half 32R1 of the specific region 32R is defined as the maximum thickness T3, and the longest length that the line segment crosses the drug layer 35 within the inner half 32R2 of the specific region 32R is defined as the maximum thickness T4.

[0113] The maximum thickness T4 of drug layer 35 in inner half 32R2 in the radial direction y of specific region 32R is, for example, preferably 1.5 times or more, more preferably 2.0 times or more, and even more preferably 2.5 times or more, the maximum thickness T3 of drug layer 35 in outer half 32R1 in the radial direction y of specific region 32R. The upper limit of the ratio of the maximum thickness T4 of drug layer 35 in inner half 32R2 in the radial direction y of specific region 32R to the maximum thickness T3 of drug layer 35 in outer half 32R1 in the radial direction y of specific region 32R is not particularly limited, and drug layer 35 may not be provided in outer half 32R1 in the radial direction y of specific region 32R, or may be very thin. For example, the maximum thickness T4 of the drug layer 35 in the inner half 32R2 in the radial direction y of the specific region 32R may be 100 times or less, or may be 50 times or less, 30 times or less, 20 times or less, or 10 times or less, of the maximum thickness T3 of the drug layer 22 in the outer half 32R1 in the radial direction y of the specific region 32R.

[0114] The above configuration reduces the influence of the drug layer 35 when the portion including the outermost end 32t of the wire 32 contacts the inner wall 10a of the first shaft 10 via the drug layer 35, and makes it easier for the portion including the outermost end 32t of the wire 32 to contact the inner wall of the first shaft 10 without the drug layer 35 in between.

[0115] As shown in Figure 13, in a vertical cross section in the longitudinal direction x, it is preferable that the maximum thickness T3 of the drug layer 35 in the outer half 32R1 in the radial direction y of the specific region 32R is smaller than the maximum thickness T2 of the drug layer 35 on the outer surface of the balloon main body portion 33 other than the specific region 32R.

[0116] The maximum thickness T2 of the drug layer 35 on the outer surface of the balloon body 33 other than the specific region 32R is preferably at least 1.2 times, more preferably at least 1.5 times, and even more preferably at least 1.8 times the maximum thickness T3 of the drug layer 35 in the outer half 32R1 of the specific region 32R in the radial direction y. There is no particular upper limit to the ratio of the maximum thickness T2 of the drug layer 35 on the outer surface of the balloon body 33 other than the specific region 32R to the maximum thickness T3 of the drug layer 35 in the outer half 32R1 of the specific region 32R in the radial direction y. The drug layer 35 may not be provided in the outer half 32R1 of the specific region 32R in the radial direction y, or may be very thin. For example, the maximum thickness T2 of the drug layer 35 on the outer surface of the balloon main body 33 other than the specific region 32R may be 100 times or less, or 50 times or less, 30 times or less, 20 times or less, or 10 times or less, of the maximum thickness T3 of the drug layer 35 in the outer half 32R1 of the specific region 32R in the radial direction y.

[0117] The above configuration reduces the influence of drug layer 35 when the portion of wire 32 including outermost end 32t contacts inner wall 10a of first shaft 10 via drug layer 35, or makes it easier for the portion of wire 32 including outermost end 32t to contact the inner wall of first shaft 10 without drug layer 35. Furthermore, because the maximum thickness T2 of drug layer 35 on the outer surface of balloon body 33 outside specific region 32R can be set to a predetermined value or greater, it becomes easier for the drug in drug layer 35 to act on the lesion when balloon 30 is inflated.

[0118] As shown in Figures 10 to 17, in a cross section perpendicular to the longitudinal direction x, it is preferable that a drug layer 35 be present between the outer edge of the cross section of the wire rod 32 facing the outer surface of the balloon main body 33 and the outer surface of the balloon main body 33. The outer edge of the cross section of the wire rod 32 facing the outer surface of the balloon main body 33 refers to the portion of the outer edge of the cross section of the wire rod 32 that faces the balloon main body 33 on the inward side in the radial direction y. If the drug layer 35 is provided in this manner, when the balloon 30 is inflated, the wire rod 32 is pressed against the outer surface of the balloon main body 33, making the drug layer 35 present between the wire rod 32 and the balloon main body 33 more likely to rupture. This makes it easier for the drug layer 35 to peel off from the balloon 30, allowing the drug to be efficiently delivered to the vascular wall.

[0119] As shown in Figures 10 to 17, in a cross section perpendicular to the longitudinal direction x, the balloon 30 preferably has a portion where the drug layer 35 is not present between the outer edge of the cross section of the wire 32 facing the outer surface of the balloon main body 33 and the outer surface of the balloon main body 33. In particular, in a cross section perpendicular to the longitudinal direction x, it is preferable that a gap 36 where the drug layer 35 is not present exists between the outer edge of the cross section of the wire 32 facing the outer surface of the balloon main body 33 and the outer surface of the balloon main body 33. This makes the drug layer 35 present between the wire 32 and the balloon main body 33 more likely to rupture when the balloon 30 is inflated. Furthermore, bodily fluids such as blood flow into the gap 36 where the drug layer 35 is not present, making it easier for the drug layer 35 present between the wire 32 and the balloon main body 33 to detach from the balloon 30.

[0120] The drug layer 35 is preferably provided on the outer surface of the balloon body 33 other than the specific region 32R. In a vertical cross section taken along the longitudinal direction x, the drug layer 35 is preferably provided over an area of ​​30% or more of the outer surface of the balloon body 33 other than the specific region 32R, more preferably 40% or more, and even more preferably 50% or more. The drug layer 35 may be provided over an even wider area of ​​the outer surface of the balloon body 33, and the drug layer 35 may be provided over 60% or more, 80% or more, or even the entire outer surface of the balloon body 33 other than the specific region 32R.

[0121] 16, the balloon 30 preferably has wing portions 34 in the deflated state. When the balloon 30 is in the deflated state, the wing portions 34 are preferably formed by folding back at least a portion of the expandable portion 31 with the inner surface of the balloon body 33 facing inward, and the wing portions 34 are preferably arranged directly or indirectly overlapping the outer surface of the expandable portion 31. This allows the outer diameter of the balloon 30 in the deflated state to be reduced.

[0122] When the balloon body 33 is folded with its inner surface facing inward to form the wing portions 34, the folding lines are preferably formed to extend substantially parallel to the longitudinal direction x. Furthermore, when the wire 32 extends obliquely with respect to the longitudinal direction x as shown in FIG. 7, the folding lines are also preferably formed to extend substantially parallel to the wire 32. Note that "parallel" here includes strict parallelism ±10°. At least a portion of the expandable portion 31 may be folded to form a clear folding line, or may be folded to form a rounded folding line.

[0123] The number of wing portions 34 formed when the balloon 30 is in a deflated state may be one or two or more. When multiple wing portions 34 are formed, the number of wing portions 34 may be, for example, two or more, three or more, four or more, six or more, or twelve or less, ten or less, or eight or less.

[0124] The number of folding lines formed when one blade portion 34 is formed may be one or two or more, but is preferably one or two. Since the expandable portion 31 can be contracted by simply providing the minimum number of folding lines necessary, it is possible to prevent the drug layers 35, which will be described later, from rubbing against each other unnecessarily and falling off.

[0125] 16, when the wing portions 34 are formed in the deflated state of the balloon 30, the balloon 30 preferably contracts so that the inner surface of the balloon main body 33 of the expandable portion 31 approaches the outer surface of the second shaft 20. At this time, at least a portion of the inner surface of the balloon main body 33 may be in contact with the outer surface of the second shaft 20. The portion of the inner surface of the balloon main body 33 that is in contact may be, for example, the second shaft 21 on the distal side of the second shaft 20. This makes it easier to reduce the maximum diameter of the balloon 30 in the deflated state.

[0126] In this case, when the balloon 30 is in a deflated state, the outermost ends 32t in the radial direction y of the wires 32 are preferably positioned further outward in the radial direction y than the outermost ends 34t in the radial direction y of the blades 34. The outermost ends 34t in the radial direction y of the blades 34 can be defined as the point for each blade 34 that is farthest from the centroid O of the balloon 30 in a cross section perpendicular to the longitudinal direction x.

[0127] When a plurality of wire rods 32 are provided and a plurality of blade portions 34 are formed, it is preferable that the outermost ends 32t of the wire rods 32 and the outermost ends 34t of the blade portions 34 that are closest to each other in the circumferential direction z in a cross section perpendicular to the longitudinal direction x satisfy the above relationship. In other words, it is preferable that the outermost ends 32t of the wire rods 32 and the outermost ends 34t of the blade portions 34 that are closest to each other in the circumferential direction z are positioned further outward in the radial direction y than the outermost ends 34t.

[0128] When multiple wires 32 are provided and multiple blade portions 34 are formed, it is preferable that all of the wires 32 and all of the blade portions 34 satisfy the above relationship. In other words, it is preferable that the distance from the centroid O to the outermost ends 32t of all of the wires 32 is longer than the distance from the centroid O to the outermost ends 34t of all of the blade portions 34.

[0129] When balloon 30 is in a deflated state, outermost ends 32t in the radial direction y of wire 32 are located further outward in the radial direction y than outermost ends 34t in the radial direction y of blades 34. This prevents blades 34 from contacting the walls of lumen 10a of first shaft 10 when balloon 30 is in a deflated state and housed in lumen 10a of first shaft 10. This prevents drug layer 35 disposed on blades 34 from rubbing against the walls of lumen 10a and falling off blades 34.

[0130] When the deflated balloon 30 is located within the lumen 10a of the first shaft 10, the outermost ends 32t of the wires 32 only need to be located radially outward in the y direction from the outermost ends 34t of the wing portions 34 of the balloon 30. That is, in the first region 32A, the outermost ends 32t of the wires 32 only need to be located radially outward in the y direction from the outermost ends 34t of the wing portions 34. When the balloon 30 is exposed outside the lumen 10a of the first shaft 10, it is not necessary for the outermost ends 32t of the wires 32 to be located radially outward in the y direction from the outermost ends 34t of the wing portions 34 of the balloon 30, even when the balloon 30 is deflated.

[0131] When a plurality of blade portions 34 are formed, the distances from the centroid O to the outermost ends 34t of the blade portions 34 may be the same or different.

[0132] 16 , in first region 32A, it is preferable that wings 34 and parts of expandable section 31 other than wings 34 do not contact the inner wall of first shaft 10, with or without drug layer 35 interposed therebetween. That is, it is preferable that wings 34 and parts of expandable section 31 other than wings 34 do not directly or indirectly contact the inner wall of first shaft 10. It is more preferable that in first region 32, drug layer 35 is formed on the outer surface of wings 34 and the outer surface of parts other than wings 34, and that the surface of drug layer 35 does not contact the inner wall of first shaft 10.

[0133] 16 , the wing portions 34 are preferably arranged overlapping the outer surface of the expandable portion 31 so as not to cover the outermost end 32t of the wire 32. It is more preferable that the wing portions 34 are arranged overlapping the outer surface of the expandable portion 31 so as not to cover the wire 32. This makes it easy to prevent the balloon body 33 and the wing portions 34 from contacting the inner wall of the first shaft 10 in the first region 32A when the proximal end 31P of the expandable portion 31 is located proximal to the distal end 10D of the first shaft 10 in the longitudinal direction x, with or without the drug layer 35 interposed therebetween.

[0134] 17 , the first shaft 10 preferably has an inner convex portion 13 that protrudes inward in the radial direction y on the inner surface of the first shaft 10. By providing the inner convex portion 13 on the first shaft 10, the inner convex portion 13 is more likely to come into contact with the outer surface of the balloon 30 when the balloon 30 is expanded in the longitudinal direction x at a position where the expandable portion 31 overlaps with the distal end 10D of the first shaft 10. Because the inner convex portion 13 is in contact with the outer surface of the balloon 30, a frictional force acts between the inner convex portion 13 and the balloon 30, making it possible to suppress displacement of the second shaft 20 relative to the first shaft 10.

[0135] As shown in Figure 17, the first shaft 10 has a cylindrical first shaft body 14, and it is preferable that an inner convex portion 13 is provided on the inner surface of the first shaft body 14. The inner convex portion 13 is provided so as to protrude inward in the radial direction y from the inner surface of the first shaft body 14. In a vertical cross section of the first shaft body 14 in the longitudinal direction x, the outer shape of the lumen of the first shaft body 14 is preferably formed into a circular shape. Therefore, it is possible to distinguish the first shaft body 14 from the inner convex portion 13.

[0136] The inner convex portion 13 preferably has an apex and a base. In the inner convex portion 13, the apex refers to the tip of the inner convex portion 13, i.e., the part of the inner convex portion 13 that is located most inward in the radial direction y, and the base refers to the boundary between the side surface of the inner convex portion 13 and the first shaft body portion 14, i.e., the part of the inner convex portion 13 that is located most outward in the radial direction y.

[0137] The inner convex portion 13 can be made of resin, metal, or a combination thereof, but is preferably made of resin. If the inner convex portion 13 is made of resin, the first shaft 10 having the inner convex portion 13 can be manufactured by resin molding, facilitating manufacturing. In this case, the inner convex portion 13 and the first shaft main body 14 are preferably made of the same resin, and it is more preferable that the first shaft main body 14 and the inner convex portion 13 are integrally molded. This facilitates manufacturing of the first shaft 10. The first shaft main body 14 may have an outer layer and an inner layer. In this case, the inner convex portion 13 is preferably made of the same resin as the inner layer of the first shaft main body 14. This makes it less likely that the inner convex portion 13 will unintentionally fall off the first shaft main body 14. Alternatively, the inner convex portion 13 and the first shaft main body 14 may be made of different resins as long as the resins constituting the inner convex portion 13 and the first shaft main body 14 are compatible to a certain extent.

[0138] The inner convex portion 13 may be a ridge. The inner convex portion 13 may be provided so as to extend in a ridge-like manner on the inner surface of the first shaft body portion 14. The inner convex portion 13 is preferably provided so as to extend in the longitudinal direction x, and in this case, it is more preferable that the inner convex portion 13 extends substantially parallel to the longitudinal direction x. The inner convex portion 13 may be provided so as to extend in the circumferential direction z. The inner convex portion 13 may be provided continuously or intermittently in the longitudinal direction x or the circumferential direction z.

[0139] Only one or more inner convex portions 13 may be provided in a vertical cross section in the longitudinal direction x of the first shaft body portion 14. In Fig. 17, the inner convex portions 13 are provided at three locations in the circumferential direction z of the first shaft body portion 14.

[0140] One inner convex portion 13 may be provided so as to extend annularly over the entire circumferential direction z. Furthermore, it is preferable that a plurality of inner convex portions 13 are provided on the first shaft body portion 14 at different positions in the circumferential direction z. That is, it is preferable that the inner convex portions 13 are provided at a plurality of locations in the circumferential direction z of the first shaft body portion 14. In this case, it is preferable that the inner convex portions 13 are arranged at approximately equal intervals in the circumferential direction z of the first shaft body portion 14. This can enhance the effect of suppressing misalignment of the second shaft 20 relative to the first shaft 10. The inner convex portions 13 are preferably provided at two or more locations in the circumferential direction z of the first shaft 10, more preferably three or more locations, and more preferably eight or fewer locations, and more preferably six or fewer locations. In this case, it is preferable that the interval between the inner convex portions 13 in the circumferential direction z is longer than the length of one inner convex portion 13 in the circumferential direction z. In a cross section perpendicular to the longitudinal direction x, the number of inner convex portions 13 may be equal to or different from the number of wire rods 32.

[0141] The cross-sectional shape of the inner convex portion 13 is not particularly limited. For example, the shape of the inner convex portion 13 in a cross section perpendicular to the longitudinal direction x may be a polygon such as a triangle or a rectangle, a partial circle shape such as a semicircle or a sector, a substantially circle, a wedge shape, a convex shape, a spindle shape, or an irregular shape. Polygons include polygons with clearly defined corners and straight sides, as well as rounded polygons with rounded corners and polygons with at least some curved sides. The inner convex portion 13 may be narrower toward the apex, may be narrower continuously toward the apex, or may be narrower in a stepped manner toward the apex. The inner convex portion 13 may also have a portion where the width increases and a portion where the width decreases toward the apex.

[0142] In a vertical cross section in the longitudinal direction x, the height of the inner convex portion 13 is preferably 0.2 times or more the width (maximum width) of the inner convex portion 13. If the inner convex portion 13 is formed in this manner, when the balloon 30 is inflated at a position where the expandable portion 31 overlaps the distal end 10D of the first shaft 10 in the longitudinal direction x, the inner convex portion 13 is more likely to contact the outer surface of the balloon 30, thereby improving the effect of suppressing displacement of the second shaft 20 relative to the first shaft 10. Note that the width of the inner convex portion 13 described here refers to the length of the inner convex portion 13 in the circumferential direction z. The inner convex portion 13 may be formed so that its width is maximum at its base, which allows the inner convex portion 13 to be stably installed on the inner surface of the first shaft main body portion 14. The height of the inner convex portion 13 is more preferably 0.4 times or more the width of the inner convex portion 13, even more preferably 0.7 times or more, and preferably 2.0 times or less, more preferably 1.8 times or less, and even more preferably 1.5 times or less.

[0143] In the first shaft 10, the inner convex portion 13 may be disposed over the entire length of the first shaft main body 14 in the longitudinal direction x, but is more preferably disposed in the distal portion when the first shaft main body 14 is divided into two equal parts in the longitudinal direction x, a distal portion and a proximal portion. This makes it easier for the inner convex portion 13 to come into contact with the outer surface of the balloon 30 when the balloon 30 is expanded at a position where the expandable portion 31 overlaps the distal end 10D of the first shaft 10 in the longitudinal direction x.

[0144] 17, the wire rod 32 and the inner convex portion 13 are preferably arranged at different positions in the circumferential direction z. This makes it easier for the wire rod 32 to fit into the space formed by the inner convex portion 13 of the first shaft 10, thereby suppressing an increase in the outer diameter of the first shaft 10. In addition, the inner convex portion 13 can also function as a guide portion for guiding the position of the wire rod 32 in the circumferential direction z.

[0145] When the balloon 30 has multiple wires 32 and the first shaft 10 has multiple inner convex portions 13, it is preferable that the wires 32 and the inner convex portions 13 of the first shaft 10 are arranged alternately in the circumferential direction z of the first shaft 10, as shown in Fig. 17. That is, it is preferable that the wires 32, inner convex portions 13, wires 32, inner convex portions 13 are arranged in this order in the circumferential direction z of the first shaft 10.

[0146] 18, the first shaft 10 preferably has an expandable / contractable portion 17 at the distal end of the first shaft 10, where the inner diameter of the first shaft 10 expands and contracts in the radial direction y. By having the first shaft 10 have the expandable / contractable portion 17, when the balloon 30 is protruded from the distal end of the first shaft 10, the inner diameter of the first shaft 10 increases at the expandable / contractable portion 17, making it easier to protrude the balloon 30 smoothly.

[0147] When the balloon 30 is expanded at a position where the expandable portion 31 overlaps the distal end 10D of the first shaft 10 in the longitudinal direction x, it is preferable that the inner diameter of the first shaft 10 increases at the expansion / contraction portion 17. Furthermore, even if the expandable portion 31 is located at a position where it overlaps the distal end 10D of the first shaft 10 in the longitudinal direction x, when the balloon 30 is deflated, it is preferable that the inner diameter of the first shaft 10 at the expansion / contraction portion 17 is smaller than when the balloon 30 is expanded. In this way, the inner diameter of the first shaft 10 at the expansion / contraction portion 17 increases or decreases as the balloon 30 expands or contracts, making it possible to adjust the length of the expandable portion 31 that contacts the lesion and also making it easier to smoothly remove the catheter 100 from the body after the procedure is completed.

[0148] The expansion / contraction section 17, whose inner diameter increases as the expandable section 31 expands, can be configured as follows. For example, as shown in FIG. 18 , the first shaft 10 may have a chamber 17A located within the sidewall of the distal end of the first shaft 10 and expanded by the supply of fluid, and a flow path 17B located within the sidewall of the first shaft 10, extending in the longitudinal direction x, and communicating with the chamber 17A. The inner diameter of the first shaft 10 can be increased in the expansion / contraction section 17 by supplying fluid to the chamber 17A from the proximal side through the flow path 17B to expand the chamber 17A. Although not shown, the first shaft 10 may have the chamber 17A, and the catheter 100 may further have a tubular member attached to the first shaft 10 and having a flow path 17B communicating with the chamber 17A of the first shaft 10. In this case, fluid can be supplied to the chamber 17A within the sidewall of the first shaft 10 through the flow path 17B of the tubular member. The tubular member may be disposed radially outward of the first shaft 10 in the radial direction y, or may be disposed in the lumen 10a of the first shaft 10. The minimum inner diameter of the expansion / contraction section 17 when the chamber 17A is expanded by injecting a fluid into the flow path 17B is larger than the minimum inner diameter of the expansion / contraction section 17 when the chamber 17A is not expanded.

[0149] 18, it is preferable that a radiopaque marker 50 be attached to the expansion / contraction section 17 of the first shaft 10. This makes it easier to visualize the expansion / contraction section 17, which is likely to come into contact with the lesion.

[0150] In the expansion / contraction portion 17, the outer surface, inner surface, inner cavity 10a, and inner surface of the first shaft 10 are A marker 50 can be placed on either one of the two.

[0151] The expansion / contraction section 17 may be arranged, for example, up to a position 50 mm proximal from the distal end 10D of the first shaft 10, up to a position 40 mm proximal from the distal end 10D of the first shaft 10, or up to a position 30 mm proximal from the distal end 10D of the first shaft 10.

[0152] The inner convex portion 13 may or may not be provided on the expansion / contraction portion 17 of the first shaft 10. Also, the inner convex portion 13 may be provided on the proximal side of the expansion / contraction portion 17 of the first shaft 10.

[0153] When the balloon 30 is expanded in the longitudinal direction x at a position where the expandable portion 31 overlaps the distal end 10D of the first shaft 10, the expansion / contraction portion 17 of the first shaft 10 preferably contacts the balloon 30, and more preferably contacts the outer surface of the balloon 30. In this case, the inner surface of the expansion / contraction portion 17 of the first shaft 10 may contact the balloon 30, or the inner surface of the marker 50 may contact the balloon 30. If the expansion / contraction portion 17 has an inner convex portion 13, it is preferable that the inner convex portion 13 of the expansion / contraction portion 17 contacts the balloon 30 when the balloon 30 is expanded in the longitudinal direction x at a position where the expandable portion 31 overlaps the distal end 10D of the first shaft 10.

[0154] 18 , the first shaft 10 may have, in its distal portion, a first section 18 and a second section 19 located proximal to the first section 18 and having an inner diameter that increases as the expandable portion 31 is expanded. In this case, the rate of change in the average inner diameter of the second section 19 before and after expansion of the expandable portion 31 is preferably greater than the rate of change in the average inner diameter of the first section 18 before and after expansion of the expandable portion 31. In the catheter 100, the rate of change in the average inner diameter is greater in the second section 19 than in the first section 18. This allows the second section 19 to withstand the stress that the first shaft 10 receives from the balloon 30 when the expandable portion 31 is expanded, and also allows the first section 18 to fix the position of the balloon 30, thereby preventing the balloon 30 from shifting positionally relative to the first shaft 10 when the expandable portion 31 is expanded.

[0155] The rate of change in the average inner diameter of the second section 19 before and after the expansion of the expandable section 31 may be 10 times or more, 20 times or more, 30 times or more, 50 times or more, or 60 times or more than the rate of change in the average inner diameter of the first section 18 before and after the expansion of the expandable section 31. Furthermore, the rate of change in the average inner diameter of the second section 19 before and after the expansion of the expandable section 31 is preferably 60 times or less, 50 times or less, 30 times or less, or 20 times or less than the rate of change in the average inner diameter of the first section 18 before and after the expansion of the expandable section 31. By setting the rates of change in the average inner diameter of the first section 18 and the second section 19 in this manner, the first section 18's effect of suppressing displacement of the balloon 30 and the second section 19's effect of absorbing stress applied to the first shaft 10 by the balloon 30 are more easily achieved.

[0156] It is preferable that the inner diameter of the first section 18 does not change substantially before and after the expansion of the expandable section 31. The rate of change in the average inner diameter of the first section 18 before and after the expansion of the expandable section 31 is preferably 5% or less, more preferably 4% or less, even more preferably 3% or less, and even more preferably 2% or less. Furthermore, the rate of change in the average inner diameter of the first section 18 before and after the expansion of the expandable section 31 may be 0%, 0.5% or more, 0.7% or more, or 1% or more. Setting the rate of change in the average inner diameter of the first section 18 in this manner makes it easier for the first section 18 to exert its effect of suppressing displacement of the balloon 30.

[0157] The rate of change in the average inner diameter of the second section 19 before and after expansion of the expandable section 31 may be 5% or more, 8% or more, 10% or more, 12% or more, or 15% or more. Furthermore, the rate of change in the average inner diameter of the second section 19 before and after expansion of the expandable section 31 is preferably 30% or less, more preferably 25% or less, and even more preferably 20% or less. By setting the rate of change in the average inner diameter of the second section 19 in this manner, the second section 19 can more easily exert its effect of absorbing the stress that the first shaft 10 receives from the balloon 30 when the balloon 30 is expanded.

[0158] In the longitudinal direction x, other sections may be arranged between the first section 18 and the second section 19, but it is preferable that the first section 18 and the second section 19 are adjacent to each other, as shown in Figure 18.

[0159] 18, in the longitudinal direction x, the second section 19 is preferably longer than the first section 18. By providing the second section 19 in this manner, the effect of the second section 19 absorbing the stress that the first shaft 10 receives from the balloon 30 when the balloon 30 is expanded can be more easily achieved. Furthermore, by making the first section 18 shorter than the second section 19, it becomes easier to fix the balloon 30 so that the first section 18 of the first shaft 10 bites into the balloon 30 when the balloon 30 is expanded.

[0160] In the longitudinal direction x, the length of the second section 19 may be 1.1 times or more, 1.2 times or more, 1.5 times or more, 2.0 times or more, or 3.0 times or more than the length of the first section 18, or may be 20.0 times or less, 15.0 times or less, 10.0 times or less, or 8.0 times or less.

[0161] In the longitudinal direction x, the length of the second section 19 may be the same as or shorter than the length of the expandable portion 31 of the balloon 30 .

[0162] In the longitudinal direction x, the distal end of the first section 18 may be located at the same position as the distal end 10D of the first shaft 10, or may be located more proximal than the distal end 10D.

[0163] In the longitudinal direction x, the first section 18 may be arranged, for example, up to a position 50 mm proximal from the distal end 10D of the first shaft 10, up to a position 40 mm proximal from the distal end 10D, or up to a position 30 mm proximal from the distal end 10D.

[0164] In the longitudinal direction x, the first section 18 may be, for example, 0.5 mm or more, 1.0 mm or more, 2.0 mm or more, 3.0 mm or more, or 10.0 mm or less, 8.0 mm or less, 5.0 mm or less.

[0165] In the longitudinal direction x, the second section 19 may be, for example, 0.55 mm or more, 1.1 mm or more, 2.2 mm or more, 3.3 mm or more, or 50 mm or less, 40 mm or less, or 30 mm or less.

[0166] The first section 18 and / or the second section 19 of the first shaft 10 may or may not have an inner convex portion 13. The first section 18 of the first shaft 10 may have an inner convex portion 13, and the second section 19 may not have an inner convex portion 13.

[0167] 18, in the second section 19, the first shaft 10 has an outer layer 10B and an inner layer 10A located radially inward of the outer layer 10B, and the inner layer 10A is preferably made of a material that is lower in hardness than the outer layer 10B. This makes it easier for the flexibility of the second section 19 to more effectively absorb the stress that the first shaft 10 receives from the balloon 30 when the expandable portion 31 is expanded.

[0168] In the second section 19, the constituent materials of the outer layer 10B and the inner layer 10A can be the same as those described for the resin constituting the first shaft 10 and / or the second shaft 20, but the inner layer 10A is preferably made of an elastic material, such as an elastomeric resin such as a polyamide elastomer, a polyester elastomer, or a polyurethane elastomer. In the second section 19, the outer layer 10B is preferably made of a resin other than an elastomeric resin.

[0169] In the first section 18, the first shaft 10 may have an outer layer 10B and an inner layer 10A. Alternatively, in the first section 18, the first shaft 10 may be composed of a single layer. When the first shaft 10 has an outer layer 10B and an inner layer 10A in the first section 18, it is preferable that the inner layer 10A be composed of a material with a higher hardness than the outer layer 10B, or that the hardness of the inner layer 10A and the outer layer 10B be the same. By setting the hardness of the outer layer 10B and the inner layer 10A in the first section 18 in this manner, the first section 18 can more easily exert its effect of suppressing displacement of the balloon 30. [Explanation of symbols]

[0170] 10: First shaft 10a: First shaft bore 10A: Inner layer 10B: Outer layer 10D: Distal end of first shaft 10d: Distal opening of first shaft 10G: Guide part 10p: Port of the first shaft 11: Distal first shaft 12: Proximal first shaft 13: Inner convex part 14: First shaft body 15: Handle 17: Enlargement and reduction section 18: First Section 19: Second Section 20: Second shaft 20a: Flow path 21: Distal second shaft 21A: Inner shaft 21B: Outer shaft 22: Proximal second shaft 23: Guidewire port 25: Hub 26:Fluid injection part 28: Tip member 30: Balloon 30A: Distal sleeve part 30B: Distal tapered section 30C: Straight pipe section 30D: Proximal tapered section 30E: Proximal sleeve part 31: Expandable section 31D: Distal end of expandable portion 31P: Proximal end of expandable section 32: Wire rod 32A: 1st area 32D: Distal end of wire 32P: Proximal end of wire 32R: Specific area 32R1: Outer half of specific area 32R2: Inner half of specific area 32t: outermost end of wire 33: Balloon body 33t: outermost end of balloon body 34: Wing 34t: outermost end of the blade 35: Drug layer 36:Void 37: Fixing member 38:Protective layer 50: Marker 100: Catheter

Claims

1. a first shaft having a longitudinal direction and a radial direction and having a lumen extending in the longitudinal direction; a second shaft disposed in the lumen and adapted to move in the longitudinal direction relative to the first shaft; a balloon disposed at a distal portion of the second shaft, the balloon having an expandable portion that expands and contracts in the radial direction, and a protruding length of the expandable portion from the first shaft that can be adjusted depending on the length of the lesion of the patient; the balloon has a drug layer disposed on an outer surface of the expandable portion; the expandable portion includes a balloon body and a wire rod disposed radially outward of the balloon body, When the balloon is in a deflated state, the radially outermost end of the wire is located radially outward of the radially outermost end of the balloon body, A catheter in which, when the proximal end of the expandable portion is located proximal to the distal end of the first shaft in the longitudinal direction, the wire has a first region that is located proximal to the distal end of the first shaft, and in the first region, the wire contacts the inner wall of the first shaft with or without the drug layer.

2. The catheter according to claim 1 , wherein the outermost end of the wire is in contact with the inner wall of the first shaft with or without the drug layer interposed therebetween.

3. The catheter according to claim 1 or 2, wherein in the first region, the wire is in contact with the inner wall of the first shaft without the drug layer therebetween.

4. The catheter according to claim 1 or 2, wherein in the first region, the wire is in contact with the inner wall of the first shaft via the drug layer.

5. the balloon has a straight tube portion, a proximal tapered portion located proximally relative to the straight tube portion, and a distal tapered portion located distally relative to the straight tube portion; The catheter according to claim 1 or 2, wherein the drug layer is disposed on the straight tube portion.

6. The catheter according to claim 1 or 2, wherein the first shaft has a guide portion on an inner wall of the first shaft that guides the wire.

7. the drug layer is provided from the surface of the wire to the outer surface of the balloon body, 3. The catheter of claim 1, wherein the maximum thickness of the drug layer within a region (hereinafter referred to as the "specific region") surrounded by a specific shape obtained by enlarging the cross-sectional outer edge of the wire rod by two times, centered on the centroid of the cross-sectional outer edge of the wire rod, in the vertical cross section in the longitudinal direction is thicker than the maximum thickness of the drug layer on the outer surface of the balloon body portion outside the specific region.

8. 3. The catheter of claim 1, wherein in the longitudinal vertical cross section, the maximum thickness of the drug layer in the radially outer half of the specific region is smaller than the maximum thickness of the drug layer in the radially inner half of the specific region.

9. 3. The catheter of claim 1, wherein in the longitudinal vertical cross section, the maximum thickness of the drug layer in the radially outer half of the specific region is smaller than the maximum thickness of the drug layer on the outer surface of the balloon body portion other than the specific region.

10. In the vertical cross section in the longitudinal direction, the cross section of the wire facing the outer surface of the balloon body The catheter according to claim 1 or 2, wherein the drug layer is present between the outer edge of the surface and the outer surface of the balloon body.

11. 3. The catheter according to claim 1, wherein in the longitudinal vertical cross section, there is a portion where the drug layer is not present between the outer edge of the cross section of the wire that faces the outer surface of the balloon body and the outer surface of the balloon body.

12. 3. The catheter according to claim 1, wherein cracks extending along the extending direction of the wire are formed on the surface of the drug layer.

13. The catheter of claim 12, wherein a protective layer is provided on an outer surface of the drug layer, the protective layer covering at least a portion of the cracks.

14. the balloon has a straight tube portion, a proximal tapered portion located proximal to the straight tube portion, a distal tapered portion located distal to the straight tube portion, a proximal sleeve portion located proximal to the proximal tapered portion, and a distal sleeve portion located distal to the distal tapered portion, a proximal end of the wire is fixed to the proximal tapered portion and / or the proximal sleeve portion; 3. The catheter according to claim 1, wherein the distal end of the wire is fixed to the distal tapered portion and / or the distal sleeve portion.

15. 3. The catheter according to claim 1, wherein the balloon has wings in a deflated state.

16. The catheter according to claim 15, wherein the wing portions are arranged overlapping the outer surface of the expandable portion so as not to cover the outermost end of the wire.

17. 3. The catheter according to claim 1, wherein the wire is made of resin, metal, or a combination thereof.

18. 3. The catheter according to claim 1, wherein the surface free energy of the material constituting the surface of the wire is different from the surface free energy of the material constituting the outer surface of the balloon body.

19. 3. The catheter according to claim 1, wherein the surface free energy of the material constituting the surface of the wire is greater than the surface free energy of the material constituting the outer surface of the balloon body.

20. The catheter according to claim 1 or 2, wherein the first shaft has an inner convex portion on an inner surface of the first shaft that protrudes inward in the radial direction.

21. The catheter according to claim 20, wherein the wire and the inner convex portion are disposed at different positions in the circumferential direction.

22. The catheter according to claim 1 or 2, wherein the first shaft has an expandable / contractable portion at a distal end of the first shaft, the inner diameter of the first shaft expanding and contracting in the radial direction.

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