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, and a balloon having an expandable part 31 capable of adjusting a protrusion length of the expandable part 31 from the first shaft 10 according to the length of a lesioned part of a patient. The balloon includes a medicine layer 35 arranged on an outer surface of the expandable part 31. The expandable part 31 includes a balloon body part 33 and a convex part 32 protruding outward in a radial direction of the balloon body part 33. The balloon includes a wing part 34 in a deflated state, and an outermost end 32t of the convex part 32 is positioned more outward in the radial direction than an outermost end 34t of the wing part 34 in the deflated state, The convex part 32 includes a first region present closer on a proximal side than a distal end of the first shaft 10, and in the first region, the convex part 32 comes in contact with an inner wall of the first shaft 10.SELECTED DRAWING: Figure 9

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] Balloon catheters with convex portions on the surface of the balloon are known (e.g., Patent Documents 1 to 5). Using such a scoring balloon catheter, the convex portions of the balloon can be inserted into the stenotic site when the balloon is inflated, effectively dilating the stenotic site. Meanwhile, in angioplasty, restenosis can occur at the dilated stenotic site. To reduce the frequency of restenosis (restenosis rate), balloon catheters with a drug loaded on the balloon surface are also known (e.g., Patent Documents 4 to 7). By using such a drug-loaded balloon catheter, the drug can be delivered to the inner wall of a body cavity such as a blood vessel by inflating the balloon at a stenotic site or lesion in the body cavity such as a blood vessel, and this is expected to prevent the occurrence of lesions such as restenosis. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-112361 [Patent Document 2] Japanese Patent Application Publication No. 2017-12678 [Patent Document 3] International Publication No. 2020 / 250611 [Patent Document 4] Special Publication No. 2008-539959 [Patent Document 5] Japanese Patent Application Laid-Open No. 2013-176507 [Patent Document 6] Special Publication No. 2008-529740 [Patent Document 7] Japanese Patent Application Laid-Open No. 2015-217260 Summary of the Invention [Problem to be solved by the invention]

[0005] The length of the lesion to which the scoring balloon catheter is applied varies, so it is necessary to select a catheter with a protrusion of a length appropriate for the length of the lesion. In case the lesion is longer than expected, a catheter with a longer protrusion may be selected. However, if the protrusion is longer than the length of the lesion, there is a risk that the protrusion will come into contact with and damage non-target tissue other than the lesion. Furthermore, if a drug is held on the balloon surface, drug loss can be a problem.

[0006] The present invention has been made in view of the above 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 has a balloon body and a protrusion protruding outward in the radial direction of the balloon body, the balloon has wings in a deflated state; in the contracted state, the radially outermost ends of the convex portions are located radially outward of the radially outermost ends of the blade portions, 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 convex portion has a first region that is located proximal to the distal end of the first shaft, and in the first region, the convex portion 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 switch 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 has protrusions, the length of the expandable portion can be adjusted to match the length of the lesion, preventing the protrusions 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 ends of the protrusions are located radially outward from the outermost ends of the wing portions of the contracted balloon. In the first region, the protrusions contact the inner wall of the first shaft with or without the drug layer, preventing the drug layer disposed on the outer surface of the expandable portion from falling off. This allows the protrusions, whose length matches the length of the lesion, to be exposed from the first shaft 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

[23] . [2] A catheter as described in [1], wherein the outermost end of the convex portion is in contact with the inner wall of the first shaft with or without the drug layer interposed therebetween. [3] A catheter according to [1] or [2], wherein in the first region, the convex portion contacts the inner wall of the first shaft without the drug layer therebetween. [4] A catheter according to [1] or [2], wherein in the first region, the convex portion contacts 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 protrusion. [7] A catheter described in any one of [1] to [6], wherein the balloon main body has a convex portion presence region and a convex portion absence region, and in a vertical cross section along the longitudinal direction, the thickness of the drug layer at the base of the convex portion is thicker than the thickness of the drug layer at the farthest point from the convex portion in the convex portion absence region. [8] A catheter described in any one of [1] to [7], wherein, in a vertical cross section in the longitudinal direction, the thickness of the drug layer at the outermost end of the convex portion is thinner than the thickness of the drug layer at the base of the convex portion. [9] A catheter described in any one of [1] to [8], wherein the balloon main body has a convex portion presence region and a convex portion absence region, and in a vertical cross section along the longitudinal direction, the thickness of the drug layer at the outermost end of the convex portion is thinner than the thickness of the drug layer at the farthest point from the convex portion in the convex portion absence region.

[10] The catheter according to any one of [1] to [9], wherein cracks extending along the extending direction of the convex portions are formed on the surface of the drug layer.

[11] A catheter as described in

[10] , 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.

[12] A catheter described in any of [1] to

[11] , wherein in a vertical cross section in the longitudinal direction, the side surface of the convex portion has a portion that moves away from an imaginary line passing through the outermost end of the convex portion and extending in the radial direction toward the outermost end of the convex portion, and a portion that is closer to the imaginary line toward the outermost end of the convex portion than the portion in question.

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

[12] , wherein in a vertical cross section in the longitudinal direction, the convex portion has a portion whose width narrows stepwise toward the outermost end.

[14] The convex portion has a first step portion adjacent to the outer surface of the balloon body and a second step portion closer to the outermost end, the first step portion narrowing in width toward the outermost end, The catheter according to

[13] , wherein the thickness of the drug layer at the base of the first stage portion is greater than the thickness of the drug layer at the base of the second stage portion.

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

[14] , wherein the protrusion is made of resin, metal, or a combination thereof.

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

[15] , wherein the surface free energy of the material constituting the surface of the convex portion is different from the surface free energy of the material constituting the outer surface of the balloon body.

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

[16] , wherein the surface free energy of the material constituting the surface of the convex portion is greater than the surface free energy of the material constituting the outer surface of the balloon body.

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

[17] , wherein, in a vertical cross section in the longitudinal direction, the thickness of the drug layer at the base of the convex portion on one side of an imaginary line passing through the outermost end of the convex portion and extending in the radial direction is thicker than the thickness of the drug layer at the base of the convex portion on the other side of the imaginary line.

[19] A catheter described in any of [1] to

[18] , wherein, in a vertical cross section in the longitudinal direction, the side of the convex portion includes a first side on one side of an imaginary line passing through the outermost end of the convex portion and extending in the radial direction, and a second side on the other side, and the average thickness of the drug layer on the first side is thicker than the average thickness of the drug layer on the second side.

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

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

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

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

[22] The catheter according to

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

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

[22] , 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. 8 is an enlarged cross-sectional view of the vicinity of a protruding portion of the balloon shown in FIG. 7. [Figure 9] FIG. 9 is a cross-sectional end view of the catheter shown in FIG. 3 taken along line IX-IX. [Figure 10] 10 is a cross-sectional end view showing a modification of the cross-sectional end view shown in FIG. 9. FIG. [Figure 11] 10 is a cross-sectional end view showing a further modification of the cross-sectional end view shown in FIG. 9. FIG. [Figure 12] 1 is a cross-sectional view perpendicular to the longitudinal direction of a balloon according to one embodiment of the present invention. FIG. [Figure 13] FIG. 13 is a cross-sectional view showing a modification of the cross-sectional view shown in FIG. [Figure 14] FIG. 13 is an enlarged cross-sectional view of the vicinity of a protruding portion of the balloon shown in FIG. [Figure 15] FIG. 15 is an enlarged cross-sectional view showing a modified example of the enlarged cross-sectional view shown in FIG. [Figure 16] 15 is an enlarged cross-sectional view showing a further variation of the enlarged cross-sectional view shown in FIG. 14, illustrating an embodiment in which a protective layer provided on the outer surface of the drug layer shown in FIG. 15 covers the cracks. [Figure 17] FIG. 15 is an enlarged cross-sectional view showing a further modification of the enlarged cross-sectional view shown in FIG. [Figure 18] FIG. 15 is an enlarged cross-sectional view showing a further modification of the enlarged cross-sectional view shown in FIG. [Figure 19] FIG. 15 is an enlarged cross-sectional view showing a further modification of the enlarged cross-sectional view shown in FIG. [Figure 20]10 is a cross-sectional end view showing a further modification of the cross-sectional end view shown in FIG. 9. FIG. [Figure 21] 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 direction and a radial direction and an inner lumen extending in the longitudinal direction; a second shaft disposed in the inner lumen of the first shaft and moving in the longitudinal direction relative to the first shaft; and a balloon disposed in a distal portion of the second shaft, the balloon having an expandable portion that expands and contracts in the radial direction, and the protruding length of the expandable portion from the first shaft being adjustable depending on the length of the lesion in the patient, the balloon having a drug layer disposed on the outer surface of the expandable portion, and the expandable portion having a balloon main body portion and a The balloon has a convex portion that protrudes radially outward from the balloon in the contracted state, and the balloon has a wing portion in the contracted state, and in the contracted state, the radially outermost end of the convex portion is located radially outward from the radially outermost end of the wing portion, and when the proximal end of the expandable portion is located proximal to the distal end of the first shaft in the longitudinal direction, the convex portion has a first region that is located proximal to the distal end of the first shaft, and in the first region, the convex portion contacts the inner wall of the first shaft with or without a drug layer.

[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 lesion in the patient, which eliminates the need to change to a different catheter depending on the length of the lesion, making catheter treatment more efficient. Also, even if the expandable portion protruding from the first shaft has a convex portion, the length of the expandable portion can be adjusted to match the length of the lesion, preventing the convex portion 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 a contracted state slides in the lumen of the first shaft, but the outermost end of the convex portion is in contact with the contracted balloon. By being positioned radially outward from the outermost ends of the loon's wings, the protrusions can have contact portions that contact the inner wall of the first shaft with or without a drug layer. This allows the drug layers arranged on the outer surface of the expandable section other than the contact portions to be kept out of contact with the inner wall of the first shaft, preventing the drug layers from falling off from the outer surface of the expandable section. As a result, protrusions of a length matching the length of the lesion can be exposed from the first shaft and applied to the lesion while preventing the drug layers from falling off, enabling 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 21. 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. 7 shows the balloon in an expanded state. FIG. 8 is an enlarged cross-sectional view of the periphery of the convex portion of the balloon shown in FIG. 7. Note that the drug layer is omitted from FIGS. 2 to 8. FIG. 9 is a cross-sectional end view taken along line IX-IX of the catheter shown in FIG. 3, showing a configuration in which the convex portions in the first region directly contact the inner wall of the first shaft without a drug layer. FIG. 10 is a cross-sectional end view showing a variation of the cross-sectional end view shown in FIG. 9, showing a configuration in which the convex portions in the first region indirectly contact the inner wall of the first shaft via a drug layer. FIG. 11 is a cross-sectional end view showing a further variation of the cross-sectional end view shown in FIG. 9, showing a configuration in which the first shaft has a guide portion. FIG. 12 is a cross-sectional view perpendicular to the longitudinal direction of a balloon according to an embodiment of the present invention. FIG. 13 is a cross-sectional view showing a variation of the cross-sectional view shown in FIG. 12. FIGS. 12 and 13 show the balloon in an expanded state. FIG. 14 is an enlarged cross-sectional view of the vicinity of the convex portions of the balloon shown in FIG. 12. FIGS. 15 to 19 are enlarged cross-sectional views showing different variations of the enlarged cross-sectional view shown in FIG. 14. Of these, FIG. 16 shows an embodiment in which a protective layer provided on the outer surface of the drug layer shown in FIG. 15 covers cracks. Figure 20 is a cross-sectional end view showing a further modification of the cross-sectional end view shown in Figure 9, showing a configuration in which the first shaft has an inner convex portion. Figure 21 is a cross-sectional view showing a further modification of the cross-sectional view shown in Figure 5. In Figure 21, 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. In this specification, for ease of understanding, the longitudinal, radial, and circumferential directions of all members will be referred to as The description will be given on the assumption that the longitudinal direction x, radial direction y, and circumferential direction z of the first shaft 10 coincide with each other.

[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, fluid is supplied to the interior of the balloon 30 through the second shaft 20 to inflate the balloon 30. In this way, the protruding length of the expandable portion 31 from the first shaft 10 can be adjusted by changing the position of the second shaft 20 relative to the first shaft 10 in the longitudinal direction x, and therefore the catheter 100 can be used to treat lesions of various sizes. This eliminates the need to prepare multiple catheters with expandable portions 31 of different lengths in the longitudinal direction x, and improves the efficiency of treatment using the catheter 100.

[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. 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 composed of one or more components. 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 having a resin coating on at least one of the inner and outer surfaces; or a combination of these, such as a combination of these connected in the longitudinal direction x. The resin tube can be manufactured, for example, by extrusion molding. Examples of hollow bodies having wires 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 wire may be one or more solid wires or one or more twisted wires. The type of mesh structure, and the number of turns and density of the coil are not particularly limited. The mesh structure or the coil may be formed with a constant density throughout the entire longitudinal direction x of the first shaft 10 and / or the second shaft 20, or may be formed with different densities 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 shape 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] As shown in Figure 7, 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, although the description in this specification exemplifies a case in which the longitudinal direction x, radial direction y, and circumferential direction z of the balloon 30 coincide with the longitudinal direction x, radial direction y, and circumferential direction z of the first shaft 10, these directions may be different from each other.

[0045] 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, which will be described later, 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.

[0046] 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.

[0047] As shown in Figures 2 to 8, the balloon 30 has protrusions 32 that protrude outward in the radial direction y of the balloon body 33. The provision of the protrusions 32 gives the balloon 30 a scoring function, and when the balloon 30 is inflated at a stenotic portion of a blood vessel, the protrusions 32 penetrate into the calcified stenotic portion, creating cracks in the stenotic portion. This allows the stenotic portion to be dilated while suppressing dissection of the vascular intima. It also makes it possible to increase the strength of the balloon 30 and prevent 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 protrusions 32 can function as a stopper to prevent unnecessary movement of the second shaft 20 relative to the first shaft 10.

[0048] By providing the convex portions 32, convex portion-existing regions 33A and convex portion-free regions 33B are formed in the balloon body 33. The balloon 30 can also be used to treat stenoses or lesions in body cavities other than blood vessels.

[0049] 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 convex portion 32 is 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 convex portion 32 is positioned distal to the distal end 10D of the first shaft 10, and the proximal end 32P of the convex portion 32 is positioned proximal to the distal end 10D of the first shaft 10. For example, the distal end 32D of the convex portion 32 may be arranged in the longitudinal direction x at the same position as the distal end 31D of the expandable portion 31, or may be arranged at 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. Furthermore, the proximal end 32P of the convex portion 32 may be arranged in the same position as the proximal end 31P of the expandable portion 31, or may be arranged at 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 portions of the protrusions 32 distal to the distal end 10D of the first shaft 10 to come into contact with the lesion, while the portions of the protrusions 32 proximal to the distal end 10D of the first shaft 10, i.e., the portions housed in the lumen 10a of the first shaft 10, do not come into unnecessary contact with the body cavity wall and can prevent displacement of the second shaft 20 relative to the first shaft 10. As a result, contact of the protrusions 32 with the stenosis can be kept to a minimum, preventing damage to non-target tissue.

[0050] 8, the protrusions 32 preferably have a base 32B and an apex 32T. In the protrusions 32, the base 32B is the boundary between the protrusions 32 and the balloon main body 33, i.e., the part located most inward of the protrusions 32 in the radial direction y, and the apex 32T is preferably the tip of the protrusions 32, i.e., the part located most outward of the protrusions 32 in the radial direction y. The apex 32T of the protrusions 32 preferably coincides with the outermost end 32t of the protrusions 32 in the radial direction y, but the apex 32T of the protrusions 32 does not have to coincide with the outermost end 32t of the protrusions 32 in the radial direction y.

[0051] As shown in FIGS. 8 to 20, the balloon body 33 and the protrusions 32 are preferably integrally molded. This facilitates the manufacture of the balloon 30. The protrusions 32 can be made of, for example, resin. If the protrusions 32 are made of resin, the balloon 30 having the protrusions 32 can be manufactured by resin molding. In this case, the protrusions 32 and the balloon body 33 are preferably made of the same resin. The balloon body 33 may have an outer layer and an inner layer. In this case, the protrusions 32 are preferably made of the same resin as the outer layer of the balloon body 33. This makes it less likely that the protrusions 32 will unintentionally fall off the balloon body 33. Alternatively, the protrusions 32 and the balloon body 33 may be made of different resins as long as the resins making up the protrusions 32 and the balloon body 33 are compatible to a certain extent.

[0052] Alternatively, the balloon body 33 and the protrusions 32 may be separate members, and the protrusions 32 may be made of metal or a combination of metal and resin. In this case, it is preferable that the portions of the protrusions 32, including the apexes 32T, are made of metal. This makes it easier for the protrusions 32 to create cracks in or incise the narrowed area when the balloon 30 is inflated. Alternatively, the entire protrusions 32 may be made of metal, or the portions of the protrusions 32, including the bases 32B, may be made of resin, and the portions of the protrusions 32, including the apexes 32T, may be made of metal. Therefore, it is preferable that the protrusions 32 are made of resin, metal, or a combination thereof.

[0053] In balloon 30, it is preferable that the surface free energy E1 of the material constituting the surface of protrusions 32 differs from the surface free energy E2 of the material constituting the outer surface of balloon 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 material 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 protrusions 32 and the surface free energy E2 of the material constituting the outer surface of balloon body 33, drug layer 35 can be selectively provided at desired locations on the surface of balloon 30.

[0054] The surface free energy E1 of the material constituting the surface of the protrusion 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 in the gas phase or the contact angle of an air bubble in the liquid phase of each material. 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.

[0055] The surface free energy E1 of the material constituting the surface of the protrusions 32 is preferably greater than the surface free energy E2 of the material constituting the outer surface of the balloon body 33. By setting the surface free energies of the materials constituting the surface of the protrusions 32 and the outer surface of the balloon body 33 in this manner, the drug solution becomes more easily intimately attached to the surface of the protrusions 32, making it easier to form a thicker drug layer 35 around the protrusions 32.

[0056] 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.

[0057] The surface free energy E1 of the material constituting the surface of the protrusions 32 is preferably at least 5 times, more preferably at least 8 times, and even more preferably at least 10 times the surface free energy E2 of the material constituting the outer surface of the balloon body 33. Setting the surface free energy E1 of the material constituting the surface of the protrusions 32 in this manner makes it easier to form a thicker drug layer 35 around the protrusions 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 1000 times or less, 500 times or less, 100 times or less, or 50 times or less the free energy E2.

[0058] The balloon body 33 is the portion of the expandable portion 31 excluding the convex portion 32 protruding outward in the radial direction y. The balloon body 33 is preferably defined as a portion having a cylindrical shape. In a vertical cross section of the balloon body 33 in the longitudinal direction x, the outer shape of the balloon body 33 is preferably formed into a circular shape. Therefore, the balloon body 33 and the convex portion 32 are separated from each other. In Fig. 8, the balloon body 33 and the protrusion 32 are shown separated by a broken line.

[0059] As shown in FIG. 7, the protrusions 32 may be ridges. The protrusions 32 may be provided so as to extend in a ridge-like pattern on the outer surface of the expandable portion 31. The protrusions 32 are preferably provided so as to extend in the longitudinal direction x. In this case, the protrusions 32 may extend substantially parallel to the longitudinal direction x of the balloon 30, or may extend spirally in the longitudinal direction x. Note that, from the viewpoints of improving the scoring function of the balloon 30 and facilitating the manufacture of a balloon 30 having the protrusions 32, it is preferable that the protrusions 32 extend substantially parallel to the longitudinal direction x of the balloon 30. The protrusions 32 may be arranged continuously or intermittently in the longitudinal direction x or the circumferential direction z.

[0060] Only one or more protrusions 32 may be provided in a vertical cross section of the expandable portion 31 in the longitudinal direction x. For example, in Fig. 9, the balloon 30 has three protrusions 32, which are spaced apart in the circumferential direction z.

[0061] As shown in Figures 9 to 12, it is preferable that multiple protrusions 32 are provided at different positions in the circumferential direction z on the expandable portion 31. That is, it is preferable that the protrusions 32 are provided at multiple locations in the circumferential direction z of the balloon 30. In this case, it is preferable that the protrusions 32 are arranged at approximately equal intervals in the circumferential direction z on the expandable portion 31. This makes it possible to create cracks in multiple locations in the narrowed portion when the balloon 30 is expanded. It is preferable that the protrusions 32 are provided at two or more locations in the circumferential direction z of the balloon 30, more preferably three or more locations, even more preferably four or more locations, and preferably eight or fewer locations, and more preferably six or fewer locations. In this case, the interval between the protrusions 32 in the circumferential direction z is preferably longer than the length of one protrusion 32 in the circumferential direction z.

[0062] The cross-sectional shape of the convex portion 32 is not particularly limited. For example, examples of the shape of the convex portion 32 in a vertical cross section of the expandable portion 31 in the longitudinal direction x include polygons such as triangles and rectangles, partial shapes of circles such as semicircles and sectors, approximately circles, wedge shapes, convex shapes, spindle shapes, and irregular shapes. 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.

[0063] The maximum width of the convex portion 32, i.e., the maximum length of the convex portion 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 its expanded state.

[0064] In a vertical cross section of the expandable portion 31 in the longitudinal direction x, the height of the convex portions 32 is preferably 0.2 times or more the width (maximum width) of the convex portions 32. If the convex portions 32 are formed in this manner, when the balloon 30 is inflated at the constricted portion, the convex portions 32 can easily penetrate into the constricted portion, thereby improving the scoring function of the convex portions 32. Furthermore, as described below, it becomes easier to form a drug layer 35 on the side surface of the convex portions 32. The width of the convex portions 32 described here refers to the length of the convex portions 32 in the circumferential direction z. The convex portions 32 may be formed so that their width is greatest at the base portion 32B, which allows the convex portions 32 to be stably disposed on the outer surface of the balloon main body portion 33. The height of the convex portions 32 is more preferably 0.4 times or more the width of the convex portions 32, 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.

[0065] As shown in FIGS. 12 and 13, the thickness of the expandable portion 31 at the portion where the convex portion 32 is provided, i.e., the thickness of the expandable portion 31 at the convex portion presence region 33A, is larger than the thickness of the expandable portion 31 at the portion where the convex portion 32 is not provided, i.e., the thickness of the expandable portion 31 at the convex portion non-presence region 33B. It is preferable that the wall thickness of the protrusion-existing region 33A is thicker than that of the non-protrusion-existing region 33B. That is, it is preferable that the inner wall of the balloon body 33 is not recessed outward in the radial direction y in the protrusion-existing region 33A. This improves the scoring function of the protrusions 32. The wall thickness (average wall thickness) of the protrusion-existing region 33A is preferably 1.5 times or more, more preferably 2.0 times or more, and even more preferably 2.5 times or more, the wall thickness (average wall thickness) of the non-protrusion-existing region 33B. There is no particular upper limit to the wall thickness of the protrusion-existing region 33A, and it may be, for example, 30 times or less, 20 times or less, or 10 times or less the wall thickness of the non-protrusion-existing region 33B.

[0066] In the balloon 30, the convex portions 32 are 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 created over a wide area of ​​the stenotic region when the balloon 30 is expanded. The convex portions 32 are preferably provided on the straight tube portion 30C, but may also be provided on the outer surface of the distal tapered portion 30B and / or the proximal tapered portion 30D. In FIG. 7, the convex portions 32 are provided so as to extend from the proximal tapered portion 30D through the straight tube portion 30C to the distal tapered portion 30B.

[0067] The balloon 30 may have an inner ridge (not shown) that protrudes inward in the radial direction y on the inner surface of the balloon 30. The ridge 32 and the inner ridge may be located at the same position in the longitudinal direction x or circumferential direction z of the balloon 30, and are preferably integrally molded, which may allow a portion of the balloon 30 to be thick-walled.

[0068] As shown in Fig. 9, the balloon 30 has wing portions 34 in its deflated state. As shown in Figs. 12 and 13, the balloon body 33 has convex portion regions 33A and non-convex portion regions 33B. When the balloon 30 is in its deflated state, the wing portions 34 are preferably formed by folding back at least a portion of the expandable portion 31 in the non-convex portion regions 33B with the inner surface of the balloon body 33 facing inward, and the wing portions 34 are preferably disposed so as to overlap directly or indirectly with the outer surface of the expandable portion 31. In this case, the wing portions 34 are preferably formed by folding back the balloon body 33 in the non-convex portion regions 33B so that the inner surface of the balloon body 33 is in contact with the inner surface, and the wing portions 34 are preferably formed from the expandable portion 31 in the non-convex portion regions 33B and do not include the expandable portion 31 in the convex portion regions 33A.

[0069] When the non-protrusion regions 33B are folded back with the inner surface of the balloon body 33 facing inward to form the wing portions 34, the folding lines are preferably formed to extend approximately parallel to the extension direction of the protrusions 32. Note that "parallel" here includes strict parallelism ±10°. At least a portion of the expandable portion 31 in the non-protrusion regions 33B may be folded back so as to form a clear folding line, or may be folded back so that the folding line is rounded.

[0070] 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.

[0071] The number of fold lines formed when one wing portion 34 is formed may be one or two or more, but is preferably one or two. This allows expandable portion 31 to be contracted by forming the minimum number of fold lines necessary, thereby preventing drug layers 35, described below, from rubbing against each other unnecessarily and falling off.

[0072] 9, the balloon 30 preferably contracts so that the inner surface of the balloon body 33 of the expandable section 31 approaches the outer surface of the second shaft 20. At this time, at least a portion of the inner surface of the balloon body 33 may be in contact with the outer surface of the second shaft 20. At least a portion of the inner surface of the main body portion 33 may be in contact with, for example, the distal second shaft 21 of the second shaft 20. This allows the maximum diameter of the balloon 30 in its deflated state to be reduced.

[0073] As shown in Figures 9 and 10, 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.

[0074] 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.

[0075] As illustrated in FIG. 16 , drug layer 35 may have a protective layer 36 to prevent the drug from eluting into the blood or dropping off during delivery to the stricture site. Preferably, protective layer 36 is included as part of drug layer 35 and constitutes the outermost layer of drug layer 35. That is, protective layer 36 may be disposed on the outer surface of drug layer 35. Protective layer 36 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 36 composed of a hydrophilic component is provided on the outer surface of drug layer 35, dissolution of protective layer 36 upon contact with body fluid is suppressed, and protective layer 36 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. The protective layer 36 may be composed of a hydrophobic component. For example, 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, if the protective layer 36 composed of a hydrophobic component is provided on the outer surface of the drug layer 35, dissolution of the protective layer 36 upon contact with the body fluid is suppressed, and the protective layer 36 can perform its protective function for the 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.

[0076] 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 36 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 36 can prevent dissolution of the protective layer 36 due to the water content of the body fluid, making it easier to maintain the protective function of the drug layer 35.

[0077] The protective layer 36 is preferably amorphous, which can enhance the protective function of the protective layer 36. Examples of components of the amorphous protective layer 36 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.

[0078] The drug constituting drug layer 35 is preferably crystalline, and it is particularly preferable that the pharmacologically active substance be crystalline. Examples of crystalline pharmacologically active substances include paclitaxel, sirolimus (rapamycin), everolimus, and zotarolimus. It is also preferable 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, it is preferable that protective layer 36 be amorphous to enhance its protective function.

[0079] The drug layer 35 may be disposed in both the convex portion-present region 33A and the convex portion-non-present region 33B of the expandable portion 31, or may be disposed over the entire expandable portion 31, i.e., over the entire convex portion-present region 33A and the entire convex portion-non-present region 33B. Alternatively, the drug layer 35 may be disposed over a part of the convex portion-present region 33A and a part of the convex portion-non-present region 33B of the expandable portion 31, or may be disposed over a part of the convex portion-present region 33A and the entire convex portion-non-present region 33B.

[0080] 9 and 10, when the balloon 30 is in a deflated state, the outermost ends 32t of the protrusions 32 in the radial direction y are located further outward in the radial direction y than the outermost ends 34t of the wing portions 34 in the radial direction y. The outermost ends 32t of the protrusions 32 in the radial direction y can be defined as the point at which the distance from the centroid O of the balloon 30 is greatest for each protrusion 32 in a cross section perpendicular to the longitudinal direction x. The outermost ends 34t of the wing portions 34 in the radial direction y are located further outward in the radial direction y than the outermost ends 34t of the wing portions 34 in the radial direction y. It can be defined as the point on the surface that is the longest distance from the centroid O of the balloon 30 for each wing 34.

[0081] When a plurality of protrusions 32 are provided and a plurality of blades 34 are formed, it is preferable that the outermost ends 32t of the protrusions 32 and the outermost ends 34t of the blades 34 that are closest to each other in the circumferential direction z satisfy the above relationship. In other words, it is preferable that the outermost ends 32t of the protrusions 32 and the outermost ends 34t of the blades 34 that are closest to each other in the circumferential direction z are positioned outward in the radial direction y from the outermost ends 34t.

[0082] When multiple protrusions 32 are provided and multiple blades 34 are formed, it is preferable that all of the protrusions 32 and all of the blades 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 protrusions 32 is longer than the distance from the centroid O to the outermost ends 34t of all of the blades 34.

[0083] When balloon 30 is in a deflated state, outermost ends 32t in the radial direction y of convex portions 32 are located further outward in the radial direction y than outermost ends 34t in the radial direction y of blade portions 34. This prevents blade portions 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 blade portions 34 from rubbing against the walls of lumen 10a and falling off blade portions 34.

[0084] When a plurality of protrusions 32 are provided, the distances from the centroid O to the outermost ends 32t of the protrusions 32 may be the same or different.

[0085] 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.

[0086] 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 convex portions 32 have a first region 32A that is located proximal to the distal end 10D of the first shaft 10. As shown in FIGS. 9 to 11 , in the first region 32A, the convex portions 32 are 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 convex portions 32 are in direct or indirect contact with the inner wall of the first shaft 10. Although not shown, if a protective layer 36 is disposed on the outside of the drug layer 35, the convex portions 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 36 interposed therebetween in the first region 32A.

[0087] In the first region 32A, the balloon 30 is preferably in a deflated state. That is, in the first region 32A, the expandable portion 31 is preferably folded to form the wing portions .

[0088] 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 the catheter 100, the outermost ends 32t of the convex portions 32 are located radially outward from the outermost ends 34t of the wing portions 34 of the deflated balloon 30 in the radial direction y, and in the first region 32A where the convex portions 32 are located proximal to the distal end 10D of the first shaft 10, the convex portions 32 are located via the drug layer 35 or through the drug layer 35. Since the protrusion 32 is in contact with the inner wall of the first shaft 10, i.e., the wall of the lumen 10a, without any intervening space, it is possible to prevent the drug layer 35 arranged in areas other than the protrusion 32 that is in contact with the inner wall of the first shaft 10 from rubbing against the wall of the lumen 10a of the first shaft 10. This makes it possible to prevent the drug layer 35 from falling off from the expandable section 31.

[0089] When the balloon 30 in a deflated state is located within the lumen 10a of the first shaft 10, it is sufficient that the outermost ends 32t of the projections 32 are located radially outward of the outermost ends 34t of the blades 34 of the balloon 30. That is, in the first region 32A, it is sufficient that the outermost ends 32t of the projections 32 are located radially outward of the outermost ends 34t of the blades 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 projections 32 to be located radially outward of the outermost ends 34t of the blades 34 of the balloon 30, even when the balloon 30 is in a deflated state.

[0090] The protrusions 32 may be in contact with the inner wall of the first shaft 10 over the entire range of the first region 32A, with or without the drug layer 35 interposed therebetween. Alternatively, the protrusions 32 may be in contact with the inner wall of the first shaft 10 over at least a portion of the first region 32A, with or without the drug layer 35 interposed therebetween. For example, as shown in FIGS. 3 to 6 , when the protrusions 32 are provided so that the height of the protrusions 32 is lower at the distal end or the proximal end of the protrusions 32, even if the distal end or the proximal end of the protrusions 32 is included in the first region 32A, the protrusions 32 may not be in contact with the inner wall of the first shaft 10 at the distal end or the proximal end of the protrusions 32.

[0091] 9 and 10 , in first region 32A, it is preferable that wings 34 and non-convex region 33B of expandable portion 31 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 non-convex region 33B of expandable portion 31 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 non-convex region 33B of expandable portion 31, and the surface of drug layer 35 does not contact the inner wall of first shaft 10.

[0092] The first region 32A is the portion of the convex portion 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 convex portion 32 formed on the expandable portion 31 is the first region 32A.

[0093] 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 convex portion 32, i.e., the convex portion 32 that is proximal to the distal end 10D of the first shaft 10 in the longitudinal direction x, is the first region 32A.

[0094] 5, when expandable portion 31 protruding from first shaft 10 is expanded, expandable portion 31 located proximal to distal end 10D of first shaft 10 may remain contracted, or may be slightly expanded to a range that fits within lumen 10a of first shaft 10. In either case, in first region 32A, convex portion 32 preferably contacts the inner wall of first shaft 10 with or without drug layer 35 interposed therebetween.

[0095] When expandable section 31 has multiple protrusions 32, it is preferable that in first region 32A, all of the multiple protrusions 32 are in direct or indirect contact with the inner wall of first shaft 10. In this case, all of protrusions 32 may be in contact with the inner wall of first shaft 10 via drug layer 35, all of protrusions 32 may be in contact with the inner wall of first shaft 10 without drug layer 35, or some of the multiple protrusions 32 may be in contact with the inner wall of first shaft 10 via drug layer 35 and the rest of the multiple protrusions 32 may be in contact with the inner wall of first shaft 10 without drug layer 35.

[0096] Alternatively, when expandable section 31 has multiple convex sections 32, in first region 32A, some of the multiple convex sections 32 may be in direct or indirect contact with the inner wall of first shaft 10, while the remainder of the multiple convex sections 32 may not be in contact with the inner wall of first shaft 10. Even in this case, it is preferable that the surface of drug layer 35 formed on the outer surface of wing section 34 or convex section-free region 33B of expandable section 31 is not in contact with the inner wall of first shaft 10.

[0097] As shown in FIGS. 9 and 10 , the outermost ends 32t of the protrusions 32 preferably contact the inner wall of the first shaft 10 with or without the drug layer 35 interposed therebetween. The outermost ends 32t of the protrusions 32 are the points at which the distance from the centroid O of the balloon 30 is greatest for each protrusion 32 in a cross section perpendicular to the longitudinal direction x. Although not shown, if a protective layer 36 is disposed on the outside of the drug layer 35, the outermost ends 32t of the protrusions 32 may contact the inner wall of the first shaft 10 via the drug layer 35 and the protective layer 36. Having the outermost ends 32t directly or indirectly contact the inner wall of the first shaft 10 increases the distance from the wing portions 34 and portions of the expandable portion 31 other than the outermost ends 32t of the protrusions 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.

[0098] 9, in first region 32A, convex portions 32 preferably contact 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 portions of convex portions 32 that contact the inner wall of first shaft 10, and convex portions 32 are in direct contact with the inner wall of first shaft 10. This prevents drug layer 35 from falling off from the portions of convex portions 32 that contact the inner wall of first shaft 10, thereby preventing loss of drug layer 35 and the adverse effects caused by such loss. Furthermore, convex portions 32 in first region 32A are portions that contribute to fixation when determining the amount of protrusion of expandable portion 31 from first shaft 10 and fixing it, and therefore, not disposing drug layer 35 on the portions of convex portions 32 that contact the inner wall of first shaft 10 has the effect of strengthening the fixation.

[0099] 10 , in first region 32A, convex portions 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 portions of convex portions 32 that are in contact with the inner wall of first shaft 10, and convex portions 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 portions of convex portions 32 that are in contact with the inner wall of first shaft 10, making it possible to retain a larger amount of drug layer 35 in expandable portion 31. Although not shown, if protective layer 36 is disposed on the outside of drug layer 35, convex portions 32 may be in contact with the inner wall of first shaft 10 via drug layer 35 and protective layer 36.

[0100] As shown in FIG. 7, the balloon 30 preferably 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. 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 tube section 30C. The distal tapered section 30B is located distal to the straight tube section 30C and connects to the distal end of the straight tube section 30C. The distal tapered portion 30B is preferably formed so that the outer diameter decreases with increasing distance from the straight tube portion 30C.

[0101] The drug layer 35 is preferably disposed in the straight pipe section 30C. Since the straight pipe section 30C is the section where the length in the radial direction y is the longest, disposing the drug layer 35 in the straight pipe section 30C allows the drug in the drug layer 35 to act efficiently on the lesion. Even if the drug layer 35 is placed in the straight tube portion 30C, the catheter 100 has the above-mentioned configuration, so that the drug layer 35 can be prevented from falling off from the straight tube portion 30C during delivery of the catheter 100 or when adjusting the protruding length of the expandable portion 31 from the first shaft 10.

[0102] The balloon 30 preferably further includes a distal sleeve portion 30A located distal to the distal tapered portion 30B and a proximal sleeve portion 30E located proximal to the proximal tapered portion 30D. The distal sleeve portion 30A is located distal to the distal tapered portion 30B and connects to the distal end of the distal tapered portion 30B. The distal sleeve portion 30A is preferably formed in a substantially cylindrical shape. The proximal sleeve portion 30E is located proximal to the proximal tapered portion 30D and connects to the proximal end of the proximal tapered portion 30D. The proximal sleeve portion 30E is preferably formed in a substantially cylindrical shape.

[0103] 3 to 7, 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.

[0104] 11, the first shaft 10 preferably has a guide portion 10G that guides the protrusions 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 protrusions 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.

[0105] When guide portion 10G is provided on the inner wall of first shaft 10, in first region 32A, convex portion 32 may be in contact with guide portion 10G with or without drug layer 35 interposed therebetween. In this case, outermost end 32t of convex portion 32 may be in contact with guide portion 10G, or a portion of convex portion 32 other than outermost end 32t may be in contact with guide portion 10G.

[0106] As shown in FIG. 11 , the guide portion 10G may be one or more recesses arranged on the inner surface of the first shaft 10. By fitting the protrusions 32 into the recesses, it is possible to prevent the protrusions 32 from shifting in position in the circumferential direction z due to rotation of the expandable portion 31. 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 extension direction of the recesses, thereby making it easier to slide the second shaft 20 relative to the first shaft 10. It is preferable that the recesses are arranged continuously in the longitudinal direction x.

[0107] Alternatively, although not shown, the guide portion 10G may have a rail-like structure arranged so as to be convex on the inner surface of the first shaft 10. The rail-like guide portion 10G guides the convex portion 32 of the balloon 30, and can prevent the convex portion 32 from shifting in position in the circumferential direction z due to rotation of the expandable portion 31.

[0108] As shown in Figures 12 and 13, the balloon body 33 has a convex portion region 33A and a convex portion non-existing region 33B. In a vertical cross section in the longitudinal direction x, the thickness of the drug layer 35 at the base 32B of the convex portion 32 is 1 / 3 the thickness of the drug layer 35 at the farthest point 33b from the convex portion 32 in the convex portion non-existing region 33B. It is preferable that the thickness of drug layer 35 is thicker than the thickness of drug layer 35 at the narrowed portion. This allows protrusions 32 to bite into the narrowed portion when balloon 30 is inflated at the narrowed portion, thereby effectively dilating the narrowed portion, and also allows 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 dilated narrowed portion because drug layer 35 is present at base 32B of protrusions 32.

[0109] The thickness of drug layer 35 at base 32B of convex portion 32 means the shortest distance from base 32B of convex portion 32 to the surface of drug layer 35 in a cross section perpendicular to longitudinal direction x (the length of arrow 35d in FIGS. 14 to 18). It is expected 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 at base 32B of convex portion 32 is defined as the shortest distance to the surface of drug layer 35 excluding the location where crack 35g has occurred.

[0110] The thickness of drug layer 35 at the farthest point 33b from convex portion 32 in convex portion-free region 33B means the length in the radial direction y from the outer surface of balloon body 33 at farthest point 33b to the surface of drug layer 35. If drug layer 35 is not present at the farthest point 33b from convex portion 32 in convex portion-free region 33B, the thickness of drug layer 35 at farthest point 33b is zero.

[0111] The farthest point 33b from the convex portion 32 in the convex portion-free region 33B is determined as follows: As shown in Fig. 13, when only one convex portion 32 is provided in a vertical cross section in the longitudinal direction x, the symmetrical point of the convex portion 32 in the circumferential direction z of the expandable portion 31 (the symmetrical point with respect to the center of the cylindrical balloon main body 33) becomes the farthest point 33b from the convex portion 32 in the convex portion-free region 33B. As shown in Fig. 12, when multiple convex portions 32 are provided in a vertical cross section in the longitudinal direction x, the midpoint in the circumferential direction z of adjacent convex portions 32 in the circumferential direction z of the expandable portion 31 becomes the farthest point 33b from the convex portion 32 in the convex portion-free region 33B.

[0112] This will be explained in more detail. As shown in FIG. 14, in a vertical cross section in the longitudinal direction x, the side of the protrusion 32 includes a first side 32a on one side of an imaginary line that passes through the apex 32T of the protrusion 32 and extends in the radial direction y, and a second side 32b on the other side. For example, when viewing the balloon 30 from the distal side, the left side of the protrusion 32 can be referred to as the first side 32a, and the right side can be referred to as the second side 32b. The protrusion 32 has bases 32B on the first side 32a and the second side 32b, respectively. When only one protrusion 32 is provided in a vertical cross section in the longitudinal direction x of the expandable section 31 as shown in FIG. 13, the midpoint between the base 32B of the first side 32a of the protrusion 32 and the base 32B of the second side 32b of the protrusion 32 in the protrusion-free region 33B is the farthest point 33b from the protrusion 32 in the protrusion-free region 33B. As shown in Figure 12, when multiple convex portions 32 are provided in a vertical cross section of the expandable portion 31 in the longitudinal direction x, the midpoint between the base 32B of the first side surface 32a of one convex portion 32 and the base 32B of the second side surface 32b of the adjacent convex portion 32 across the convex portion-free region 33B from the first side surface 32a of the convex portion 32 is the farthest point 33b from the convex portion 32 in the convex portion-free region 33B.

[0113] The number of bases 32B of the convex portions 32 in a vertical cross section in the longitudinal direction x is twice the number of convex portions 32, i.e., the number corresponding to the bases 32B of the first side surface 32a and the bases 32B of the second side surface 32b of each convex portion 32, but in the expandable portion 31, the thickness of the drug layer 35 at at least one base 32B of the multiple bases 32B of the convex portions 32 is formed to be thicker than the thickness of the drug layer 35 at the farthest point 33b from the convex portion 32 in the convex portion-free region 33B. When multiple convex portions 32 are provided in a vertical cross section of the expandable portion 31 in the longitudinal direction x, multiple convex portions 32 form multiple convex portion-free regions 33B, and the thickness of the drug layer 35 at at least one of the base portions 32B of the multiple convex portions 32 is formed to be thicker than the average thickness of the drug layer 35 at the farthest point 33b from the convex portion 32 in the multiple convex portion-free regions 33B, and preferably is formed to be thicker than each thickness of the drug layer 35 at the farthest point 33b from the convex portion 32 in the multiple convex portion-free regions 33B. Furthermore, it is preferable that the thickness of the drug layer 35 at the base 32B of at least one of the first side surface 32a and the second side surface 32b of each convex portion 32 is formed to be thicker than the average thickness of the drug layer 35 at the farthest point 33b from the convex portion 32 in the multiple convex portion-free regions 33B, and it is more preferable that the thickness is formed to be thicker than each thickness of the drug layer 35 at the farthest point 33b from the convex portion 32 in the multiple convex portion-free regions 33B.

[0114] The thickness of drug layer 35 at base 32B of convex portion 32 and the thickness of drug layer 35 at point 33b farthest from convex portion 32 in convex-free region 33B can be determined, for example, as follows: Balloon 30 is cut, for example, at straight tube portion 30C in a direction perpendicular to longitudinal direction x, and balloon body 33 is held in a state where it is approximately circular. Then, the thickness of drug layer 35 at base 32B of convex portion 32 and the thickness of drug layer 35 at point 33b farthest from convex portion 32 in convex-free region 33B are measured. Alternatively, the balloon 30 in a contracted state may be cut, for example, at the straight tube portion 30C in a direction perpendicular to the longitudinal direction x, and the outer periphery of the convex portion-free region 33B between the convex portions 32 of the balloon 30 in the contracted state may be measured. The midpoint of the outer periphery between the convex portions 32 may be defined as the farthest point 33b, and the thickness of the drug layer 35 at the base 32B of the convex portion 32 and the thickness at the farthest point 33b from the convex portion 32 in the convex portion-free region 33B may be measured.

[0115] The thickness of drug layer 35 at base 32B of convex portion 32 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 thickness of drug layer 35 at point 33b farthest from convex portion 32 in convex-non-existing region 33B. The upper limit of the ratio of the thickness of drug layer 35 at base 32B of convex portion 32 to the thickness of drug layer 35 at point 33b farthest from convex portion 32 in convex-non-existing region 33B is not particularly limited, and drug layer 35 may be absent or may be thin at point 33b farthest from convex portion 32 in convex-non-existing region 33B. For example, the thickness of drug layer 35 at base 32B of convex portion 32 may be 100 times or less, 50 times or less, 30 times or less, 20 times or less, or 10 times or less the thickness of drug layer 35 at point 33b farthest from convex portion 32 in convex-non-existing region 33B.

[0116] In balloon 30, it is sufficient that the thickness of drug layer 35 at base 32B of convex portion 32 is thicker than the thickness of drug layer 35 at convex-free region 33B at farthest point 33b from convex portion 32 in at least a portion of straight tube portion 30C in the longitudinal direction x. Preferably, drug layer 35 is formed in this manner in at least a portion of the central region in the longitudinal direction x of straight tube portion 30C, more preferably, drug layer 35 is formed in this manner in at least half of the central region in the longitudinal direction x of straight tube portion 30C, and even more preferably, drug layer 35 is formed in this manner in at least two-thirds of the central region in the longitudinal direction x of straight tube portion 30C. For example, assuming that the proximal end of straight tube section 30C is 0% and the distal end is 100% relative to the longitudinal direction x of straight tube section 30C, a range of 25% to 75% of straight tube section 30C is cut radially at six locations at 10% intervals, and the thickness of drug layer 35 at each cut cross section is measured, and it is preferable that the drug layer 35 is formed in this manner at three or more locations. This makes it possible to determine that the thickness of drug layer 35 at base 32B of convex portion 32 is thicker than the thickness of drug layer 35 at point 33b in convex portion-free region 33B farthest from convex portion 32 in at least half of the central region in the longitudinal direction x of straight tube section 30C. The drug layer 35 may be formed so that the thickness of the drug layer 35 at the base 32B of the convex portion 32 is thicker than the thickness of the drug layer 35 at the farthest point 33b from the convex portion 32 in the convex portion-free region 33B throughout the central region in the longitudinal direction x of the straight tube portion 30C, and the drug layer 35 may be formed in this manner throughout the longitudinal direction x of the straight tube portion 30C.

[0117] The above description of the formation of drug layer 35 in the longitudinal direction x of straight tube portion 30C will also be referred to in various descriptions below regarding the formation of drug layer 35 in a vertical cross section in the longitudinal direction x.

[0118] 14, in a vertical cross section in the longitudinal direction x, the thickness of drug layer 35 at outermost end 32t of convex portion 32 is preferably thinner than the thickness of drug layer 35 at base portion 32B of convex portion 32. This reduces the influence of drug layer 35 when outermost end 32t of convex portion 32 is in contact with inner wall 10a of first shaft 10 via drug layer 35.

[0119] 12 and 13, balloon body 33 has convex portion-existing region 33A and convex portion-absent region 33B, and in a vertical cross section in longitudinal direction x, the thickness of drug layer 35 at outermost end 32t of convex portion 32 is preferably thinner than the thickness of drug layer 35 at point 33b in convex portion-absent region 33B farthest from convex portion 32. This reduces the influence of drug layer 35 when outermost end 32t of convex portion 32 is in contact with inner wall 10a of first shaft 10 via drug layer 35, and enables convex portion-absent region 33B to retain a predetermined amount of drug layer 35 while preventing drug layer 35 from falling off.

[0120] The thickness of the drug layer 35 at the outermost end 32t of the convex portion 32 can be calculated as the shortest length from the outermost end 32t of the convex portion 32 to the surface of the drug layer 35 in a vertical cross section in the longitudinal direction x, similar to the thickness of the drug layer 35 at the base 32B of the convex portion 32.

[0121] As shown in Figure 15, it is preferable that cracks 35g extending along the extension direction of convex portions 32 are formed on the surface of drug layer 35. Figure 15 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 14. 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 provided from the surface of convex portions 32 to the outer surface of balloon main 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.

[0122] The cracks 35g may be formed to extend parallel to the extension direction of the protrusions 32 when viewed from the outside of the balloon 30, or at least a portion of the cracks 35g may be formed to extend obliquely to the extension direction of the protrusions 32. It is sufficient that the cracks 35g as a whole are formed to extend along the extension direction of the protrusions 32. The cracks 35g may be formed to extend continuously along the protrusions 32, or may be formed to extend intermittently. Furthermore, multiple cracks 35g extending along the protrusions 32 may be arranged partially side by side with each other.

[0123] Cracks 35g may be formed so as to extend from the surface of drug layer 35 to the surfaces of protrusions 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 terminate inside drug layer 35. Cracks 35g on the surface of drug layer 35 are preferably formed within protrusion-existing region 33A. Alternatively, cracks 35g on the surface of drug layer 35 may be formed in a portion of protrusion-free region 33B that is close to protrusion-existing region 33A. By forming cracks 35g in this manner, when balloon 30 is inflated at a stricture, drug layer 35 provided on the surfaces of protrusions 32 is more likely to peel off from the surface of balloon 30, starting from cracks 35g.

[0124] As shown in FIG. 16, a protective layer 36 may be provided on the outer surface of the drug layer 35, and the protective layer 36 may cover at least a portion of the crack 35g. FIG. 16 shows a cross-sectional view of the balloon 30 shown in FIG. 15 , in which a protective layer 36 is provided on the outer surface of the drug layer 35 so as to cover the crack 35g. By providing the protective layer 36 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 balloon 30 to the stricture, which could cause the drug layer 35 to fall off or the drug to elute from the drug layer 35. The protective layer 36 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 36 be provided so as to penetrate into the crack 35g and fill at least a portion of the crack 35g.

[0125] 17, in a vertical cross section in the longitudinal direction x, the side surface of the protrusion 32 preferably has a portion that moves away from an imaginary line passing through the outermost end 32t of the protrusion 32 and extending in the radial direction y toward the outermost end 32t of the protrusion 32, and a portion closer to the outermost end 32t than the portion that moves closer to the imaginary line toward the outermost end 32t of the protrusion 32. In this case, the vicinity of the base 32B of the protrusion 32 can be formed to be recessed. This allows more drug layer 35 to be formed on the base 32B of the protrusion 32.

[0126] 18, in a cross section perpendicular to the longitudinal direction x, the protrusions 32 may have a portion whose width narrows in a stepped manner toward the outermost ends 32t. This allows the portions of the protrusions 32 including the outermost ends 32t to be sharpened, and the portions of the protrusions 32 including the bases 32B to be wider, thereby improving the efficiency with which the balloon body 33 and the protrusions 32 dilate the narrowed area while stably connecting the balloon body 33 and the protrusions 32.

[0127] In this case, protrusion 32 has a first step portion 32B1 adjacent to the outer surface of balloon body 33 and a second step portion 32T1 closer to outermost end 32t than first step portion 32B1, as portions whose width narrows in a stepwise manner toward outermost end 32t, and it is preferable that the thickness of drug layer 35 at the base of first step portion 32B1 is thicker than the thickness of drug layer 35 at the base of second step portion 32T1. This makes it possible to reduce the influence of drug layer 35 when outermost end 32t of protrusion 32 is in contact with inner wall 10a of first shaft 10 via drug layer 35, while allowing base 32B of protrusion 32 to hold a predetermined amount of drug layer 35.

[0128] 19, in a vertical cross section in the longitudinal direction x, the thickness of drug layer 35 at base 32B of convex portion 32 on one side of an imaginary line passing through outermost end 32t of convex portion 32 and extending in radial direction y, i.e., on first side surface 32a side, is preferably thicker than the thickness of drug layer 35 at base 32B of convex portion 32 on the other side of the imaginary line, i.e., on second side surface 32b side. This ensures that second side surface 32b of convex portion 32 can penetrate into the narrowed portion, and more drug layer 35 is held on first side surface 32a of convex portion 32, allowing the drug to be transferred to the narrowed portion more efficiently when balloon 30 is inflated at the narrowed portion.

[0129] 19, in a cross section perpendicular to the longitudinal direction x, the side surfaces of the protrusions 32 include a first side surface 32a on one side of an imaginary line that passes through the outermost end 32t of the protrusions 32 and extends in the radial direction y, and a second side surface 32b on the other side, and it is preferable that the average thickness of the drug layer 35 on the first side surface 32a is thicker than the average thickness of the drug layer 35 on the second side surface 32b. In this case, as in the above case, the second side surface 32b of the protrusions 32 ensures the ability to penetrate into the narrowed portion, and a larger amount of the drug layer 35 is held on the first side surface 32a of the protrusions 32, so that when the balloon 30 is inflated at the narrowed portion, the drug can be transferred to the narrowed portion more efficiently.

[0130] 9 and 10, the wing portions 34 are preferably arranged overlapping the outer surface of the expandable portion 31 so as not to cover the outermost ends 32t of the convex portions 32. This makes it easy to prevent 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.

[0131] 20 , 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, 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.

[0132] As shown in Figure 20, the first shaft 10 has a cylindrical first shaft body 14, and an inner convex portion 13 is preferably 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, the first shaft body 14 and the inner convex portion 13 can be distinguished.

[0133] The inner convex portion 13 preferably has an apex and a base, similar to the convex portion 32. 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 with the first shaft body portion 14 on the side surface of the inner convex portion 13, i.e., the part of the inner convex portion 13 that is located most outward in the radial direction y.

[0134] 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.

[0135] 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.

[0136] 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. 20, the inner convex portions 13 are provided at three locations in the circumferential direction z of the first shaft body portion 14.

[0137] 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. The number of inner convex portions 13 may be equal to or different from the number of convex portions 32.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 20, the convex portions 32 and the inner convex portions 13 are preferably arranged at different positions in the circumferential direction z. This makes it easier for the convex portions 32 of the balloon 30 to fit into the space formed by the inner convex portions 13 of the first shaft 10, thereby preventing an increase in the outer diameter of the first shaft 10. The inner convex portions 13 can also function as guide portions for guiding the position of the convex portions 32 of the balloon 30 in the circumferential direction z.

[0142] When the balloon 30 has multiple convex portions 32 and the first shaft 10 has multiple inner convex portions 13, it is preferable that the convex portions 32 of the balloon 30 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. 20. That is, it is preferable that the convex portions 32, inner convex portions 13, convex portions 32, inner convex portions 13 are arranged in this order in the circumferential direction z of the first shaft 10.

[0143] 21 , 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.

[0144] 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.

[0145] 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. 21 , 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.

[0146] 21, 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.

[0147] In the expansion / contraction section 17, a marker 50 can be placed on at least one of the outer surface, inner surface, lumen 10a, and side wall of the first shaft 10.

[0148] 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.

[0149] 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.

[0150] 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.

[0151] 21 , 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, it is preferable that the rate of change in the average inner diameter of the second section 19 before and after expansion of the expandable portion 31 is 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.

[0152] 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 10 times or more, 20 times or more, 30 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. 10 times or more, 50 times or more, or 60 times 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 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 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, it becomes easier to further demonstrate the effect of the first section 18 in suppressing displacement of the balloon 30 and the effect of the second section 19 in absorbing the stress that the first shaft 10 receives from the balloon 30.

[0153] 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.

[0154] 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.

[0155] 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 21.

[0156] 21 , 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 second section 19 is more likely to absorb the stress that the first shaft 10 receives from the balloon 30 when the balloon 30 is expanded. Furthermore, by making the first section 18 shorter than the second section 19, the first section 18 of the first shaft 10 can more easily dig into the balloon 30 to fix the balloon 30 when the balloon 30 is expanded.

[0157] 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.

[0158] 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 .

[0159] 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.

[0160] 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.

[0161] 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.

[0162] 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.

[0163] 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.

[0164] 21, 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.

[0165] 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.

[0166] 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]

[0167] 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: Convex 32a: First side of the convex part 32b: Second side of the convex part 32A: 1st area 32D: Distal end of the convex part 32P: proximal end of convex part 32B: Base 32B1: 1st stage part 32T:Top 32T1: 2nd stage part 32t: outermost end of the convex part 33: Balloon body 33A: Convex area 33B: Area without convexities 33b:Farthest point from the convex part 34: Blade 34t: outermost end of the blade 35: Drug layer 35d: Arrow indicating drug layer thickness 35g: Crack 36:Protective layer 50: Marker 100: Catheter

Claims

1. a first shaft having a longitudinal direction and a radial direction and 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 has a balloon body and a protrusion protruding outward in the radial direction of the balloon body, the balloon has wings in a deflated state; in the contracted state, the radially outermost ends of the convex portions are located radially outward of the radially outermost ends of the blade portions, 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 convex portion has a first region that is located proximal to the distal end of the first shaft, and in the first region, the convex portion 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 convex portion 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 protrusions are 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 protrusions are 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 the inner wall of the first shaft that guides the protrusion.

7. 3. The catheter according to claim 1, wherein the balloon body has a convex portion-existing region and a convex portion-nonexisting region, and in a vertical cross section along the longitudinal direction, the thickness of the drug layer at the base of the convex portion is thicker than the thickness of the drug layer at the farthest point from the convex portion in the convex portion-nonexisting region.

8. The catheter according to claim 1 or 2, wherein, in a cross section perpendicular to the longitudinal direction, the thickness of the drug layer at the outermost ends of the protrusions is thinner than the thickness of the drug layer at the bases of the protrusions.

9. 3. The catheter according to claim 1, wherein the balloon body has a convex portion-existing region and a convex portion-nonexisting region, and in a vertical cross section along the longitudinal direction, the thickness of the drug layer at the outermost end of the convex portion is thinner than the thickness of the drug layer at the farthest point from the convex portion in the convex portion-nonexisting region.

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

11. The catheter of claim 10, further comprising a protective layer on an outer surface of the drug layer, the protective layer covering at least a portion of the cracks.

12. 3. The catheter according to claim 1, wherein, in a vertical cross section in the longitudinal direction, the side surface of the convex portion has a portion that moves away from an imaginary line passing through the outermost end of the convex portion and extending in the radial direction toward the outermost end of the convex portion, and a portion, closer to the outermost end than the portion, that moves closer to the imaginary line toward the outermost end of the convex portion.

13. 3. The catheter according to claim 1, wherein, in a vertical cross section in the longitudinal direction, the convex portion has a portion whose width narrows stepwise toward the outermost end.

14. The convex portion has a first step portion adjacent to the outer surface of the balloon body and a second step portion closer to the outermost end, the first step portion narrowing in width toward the outermost end, The catheter of claim 13, wherein the thickness of the drug layer at the base of the first step is greater than the thickness of the drug layer at the base of the second step.

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

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

17. 3. The catheter according to claim 1, wherein the surface free energy of the material constituting the surfaces of the convex portions is greater than the surface free energy of the material constituting the outer surface of the balloon body.

18. A catheter as described in claim 1 or 2, wherein, in a vertical cross section along the longitudinal direction, the thickness of the drug layer at the base of the convex portion on one side of an imaginary line passing through the outermost end of the convex portion and extending in the radial direction is thicker than the thickness of the drug layer at the base of the convex portion on the other side of the imaginary line.

19. 3. A catheter as described in claim 1 or 2, wherein, in a vertical cross section in the longitudinal direction, the side of the convex portion includes a first side on one side and a second side on the other side of an imaginary line passing through the outermost end of the convex portion and extending in the radial direction, and the average thickness of the drug layer on the first side is thicker than the average thickness of the drug layer on the second side.

20. The catheter according to claim 1 or 2, wherein the wing portions are arranged overlapping the outer surface of the expandable portion so as not to cover the outermost ends of the convex portions.

21. 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.

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

23. 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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