Balloon for balloon catheter and balloon catheter

Abstract

Provided is a balloon for a balloon catheter, wherein the balloon has a balloon body part (16) and protrusions (21) protruding outward in the radial direction on the outer surface of the balloon body part (16), and a drug layer (31) is provided on the end surfaces (22) of the protrusions (21).

Description

Balloon for balloon catheter and balloon catheter

[0001] The present invention relates to a balloon for a balloon catheter having a drug retained on its surface, and a balloon catheter equipped with the balloon.

[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 dilates the stenotic area using a balloon catheter.

[0003] Balloon catheters with ridges on the surface of the balloon are known (see, for example, Patent Documents 1 to 5). When such a balloon catheter is used, the ridges of the balloon bite 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 such restenosis (restenosis rate), balloon catheters with a drug loaded on the balloon surface are also known (see, for example, Patent Documents 4 to 7). By using such a drug-loaded balloon catheter, the drug can be delivered to the inner wall of the body cavity, such as the vascular wall, by inflating the balloon at a stenotic site or lesion in a body cavity, such as a blood vessel, and this is expected to prevent the occurrence of restenosis.

[0004] Japanese Patent Application Laid-Open No. 2009-112361 Japanese Patent Application Laid-Open No. 2017-12678 International Publication No. 2020 / 250611 Japanese Patent Application Laid-Open No. 2008-539959 Japanese Patent Application Laid-Open No. 2013-176507 Japanese Patent Application Laid-Open No. 2008-529740 Japanese Patent Application Laid-Open No. 2015-217260

[0005] A balloon catheter with a drug retained on its surface can deliver the drug to the inner wall of a body cavity, such as a blood vessel, by expanding the balloon at a stenosis or lesion in the body cavity, such as a blood vessel. In this case, it is desirable for the drug to gradually penetrate the inner wall of the body cavity, rather than being supplied all at once. This can prevent, for example, the formation of an aneurysm due to drug overdose. The present invention was made in consideration of the above circumstances, and its purpose is to provide a balloon for a balloon catheter that can deliver a drug to the inner wall of a body cavity, such as a blood vessel, in a sustained manner, and a balloon catheter equipped with the balloon.

[0006] The balloon for a balloon catheter of the present invention, which has been able to solve the above-mentioned problems, and a balloon catheter equipped with the balloon, are as follows: [1] A balloon for a balloon catheter having a longitudinal axis direction extending from the proximal side to the distal side and radial and circumferential directions perpendicular to the longitudinal axis direction, the balloon having a balloon main body and ridges protruding radially outward from the outer surface of the balloon main body, with a drug layer provided on the end surfaces of the ridges. [2] The balloon described in [1], which has a straight tube section, a proximal tapered section located proximal to the straight tube section, and a distal tapered section located distal to the straight tube section, with the drug layer provided on the end surfaces of the ridges on the straight tube section. [3] The balloon described in [1] or [2], wherein the thickness of the drug layer at the base of the end surface is thicker than the thickness of the drug layer at the apex of the end surface. [4] The balloon according to any one of [1] to [3], wherein the ridges are arranged in a line in the longitudinal axis direction, interruptions are formed between the ridges, and the drug layer is provided on the end surfaces of the ridges facing the interruptions. [5] The balloon according to [4], wherein the interruptions include specific interruptions on which the drug layer is provided that satisfy the following requirement: (Requirement) The drug layer is provided from the distal end surface of the ridge adjacent to the proximal side of the specific interruption to the proximal end surface of the ridge adjacent to the distal side of the specific interruption. [6] The balloon according to [4] or [5], wherein the interruptions include specific interruptions on which the drug layer is provided that satisfy the following requirement: (Requirement) In a cross section passing through the apex of the ridge along the longitudinal axis direction and the radial direction, the thickness of the drug layer at the base of the end face on the distal side of the ridge adjacent to the proximal side of the specific interruption and the thickness of the drug layer at the base of the end face on the proximal side of the ridge adjacent to the distal side of the specific interruption are greater than the thickness of the drug layer at the center of the specific interruption in the longitudinal axis direction. [7] The balloon according to any of [4] to [6], wherein the interruption includes a specific interruption on which the drug layer is provided that satisfies the following requirement:(Requirements) In a cross section passing through the apex of the ridge, along the longitudinal axis and the radial direction, the distal end face of the ridge adjacent to the proximal side of the specific interruption has a portion extending radially from the base of the end face toward the apex and / or a portion extending toward the distal side, and the proximal end face of the ridge adjacent to the distal side of the specific interruption has a portion extending radially from the base of the end face toward the apex and / or a portion extending toward the proximal side. [8] The balloon described in [7], wherein a portion of the distal end face of the ridge adjacent to the proximal side of the specific interruption is in contact with a portion of the proximal end face of the ridge adjacent to the distal side of the specific interruption. [9] The balloon described in any of [4] to [8], wherein the interruption includes a specific interruption provided with the drug layer that satisfies the following requirement: (Requirements) The outer surface of the balloon is divided circumferentially into a ridge-present region and a ridge-free region, and in a cross section perpendicular to the longitudinal axis direction passing through the center of the longitudinal axis direction of the specific discontinuity, the average thickness of the drug layer at the specific discontinuity is greater than the average thickness of the drug layer in the ridge-free region.

[10] The balloon described in any of [1] to [9], wherein the end faces of the ridges are recessed.

[11] The balloon described in any of [1] to

[10] , wherein the surface of the drug layer is formed with a crack extending along the base of the end face of the ridge.

[12] The balloon described in any of [1] to

[11] , wherein the ridges are formed in multiple steps, and wherein the surface of the drug layer is formed with a crack extending along the base of any step of the end face of the ridge.

[13] The balloon described in any of [1] to

[12] , wherein the drug constituting the drug layer is crystalline.

[14] The balloon according to any one of [1] to

[13] , wherein the surface free energy of the material constituting the surface of the ridges is different from the surface free energy of the material constituting the outer surface of the balloon main body.

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

[13] , wherein the surface free energy of the material constituting the surface of the ridges is greater than the surface free energy of the material constituting the outer surface of the balloon main body.

[16] The balloon according to any one of [1] to

[15] , wherein the ridges are made of resin, metal, or a combination thereof.

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

[16] , wherein the outer surface of the balloon is divided circumferentially into a ridge-containing region and a ridge-free region, and when the balloon is in a deflated state, the balloon is folded back at the ridge-free region with the inner surface of the balloon body facing inward to form folded wing sections where the ridge-free regions overlap, and the folded wing sections are arranged overlapping the outer surface of the balloon and cover the tops of the ridges.

[18] The balloon according to any one of [1] to

[16] , wherein the outer surface of the balloon is divided circumferentially into a ridge-containing region and a ridge-free region, and when the balloon is in a deflated state, the balloon is folded back at the ridge-free region with the inner surface of the balloon body facing inward to form folded wing sections where the ridge-free regions overlap, and the folded wing sections are arranged overlapping the outer surface of the balloon so as not to cover the tops of the ridges.

[19] A balloon catheter comprising the balloon according to any one of [1] to

[18] .

[0007] The balloon for a balloon catheter of the present invention has ridges on its outer surface and a drug layer on the end surface of the ridges. Therefore, when a balloon catheter equipped with the present invention is used to inflate the balloon at a stenosis or lesion in a body cavity such as a blood vessel, the ridges penetrate the stenosis or lesion, effectively dilating it, and a drug can be deposited near the portion of the dilated stenosis or lesion where the ridges have penetrated. The drug deposited in this manner is not delivered all at once to the interior wall of the body cavity, but rather gradually penetrates into the interior wall of the body cavity through the ruptured portions where the ridges have penetrated. This allows the drug to be delivered to the interior wall of the body cavity in a sustained manner.

[0008] 1 shows an example of the configuration of a balloon catheter according to an embodiment of the present invention, and is a side view of the balloon catheter excluding the drug layer on the balloon surface.

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[0099] [0 11 shows a cross-sectional view of a ridge having a drug layer provided on its end face, taken along the direction of extension of the ridge. 12 shows another example of a ridge having a drug layer provided on its end face and cracks formed in the surface of the drug layer, taken along the direction of extension of the ridge. 13 shows a cross-sectional view of a ridge having a drug layer provided on its end face, taken along the direction of extension of the ridge. 14 shows an example of a configuration in which a protective layer is provided on the outer surface of a drug layer provided on the end face of a ridge in the cross-sectional view of a ridge having a drug layer provided on an interrupted portion of a ridge, taken along the direction of extension of the ridge. 15 shows a cross-sectional view of the XVII-XVII portion of the interrupted portion of the ridge shown in FIG. 16 shows an example of a ridge having a drug layer provided on its interrupted portion and cracks formed in the surface of the drug layer, taken along the direction of extension of the ridge. 18 shows another example of a ridge in which a drug layer is provided at the discontinuity of the ridge and cracks are formed on the surface of the drug layer, and is a cross-sectional view of the ridge along the extension direction of the ridge. 19 shows a perspective view of the discontinuity of the ridge shown in FIG. 18. 20 shows an example of a configuration in which a protective layer is provided on the outer surface of the drug layer provided at the discontinuity of the ridge in the cross-sectional view of the ridge along the extension direction of the ridge shown in FIG. 28. 21 shows another example of a ridge provided on a balloon, and is a perspective view of the ridge.1 shows another example of a ridge in which a drug layer is provided at the discontinuous portion of the ridge, and is a cross-sectional view of the ridge along the extension direction of the ridge. 2 shows another example of a ridge in which a drug layer is provided at the discontinuous portion of the ridge, and is a cross-sectional view of the ridge along the extension direction of the ridge. 3 shows another example of a ridge provided on a balloon, and is a perspective view of the ridge. 4 shows another example of a ridge provided on a balloon, and is a cross-sectional view of the ridge perpendicular to the longitudinal axis direction of the balloon. 5 shows another example of a ridge in which a drug layer is provided on the end surface of the ridge and cracks are formed in the surface of the drug layer, and is a cross-sectional view of the ridge along the extension direction of the ridge. 6 shows an example of a folded state of the balloon shown in FIG. 5, and is a vertical cross-sectional view of the folded balloon along the longitudinal axis direction. 7 shows another example of a folded state of the balloon shown in FIG. 5, and is a vertical cross-sectional view of the folded balloon along the longitudinal axis direction.

[0009] The present invention will be described in detail below based on the following embodiments. However, 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. Furthermore, the dimensions of various components in the drawings may differ from the actual dimensions, as priority is given to helping understand the features of the present invention.

[0010] A balloon for a balloon catheter according to an embodiment of the present invention and an example of a balloon catheter equipped with the balloon will be described with reference to the drawings. Figures 1 to 7 show an example of a balloon catheter without the drug layer. Figure 1 shows a side view of the balloon catheter, Figure 2 shows a cross-sectional view of the balloon catheter shown in Figure 1 taken along II-II, Figure 3 shows a cross-sectional view of the balloon catheter shown in Figure 1 taken along III-III, Figure 4 shows a perspective view of the balloon equipped in the balloon catheter shown in Figure 1, Figure 5 shows a perspective view of another example of a balloon equipped in a balloon catheter, Figure 6 shows a vertical cross-sectional view of the longitudinal axis of the balloon shown in Figures 4 and 5 at the location of the ridges, and Figure 7 shows an enlarged cross-sectional view of the ridges of the balloon shown in Figure 6. Figure 1 shows an example of a rapid exchange type balloon catheter.

[0011] The balloon catheter 1 has a shaft 2 and a balloon 10 provided on the outside of the shaft 2. The balloon catheter 1 has a proximal side and a distal side, and the balloon 10 is provided on the distal portion of the shaft 2. The proximal side of the balloon catheter 1 refers to the direction toward the user (operator) in the direction of extension of the balloon catheter 1, and the distal side refers to the opposite direction from the proximal side, i.e., the direction toward the treatment target. The direction from the proximal side to the distal side of the balloon catheter 1 is referred to as the longitudinal axis direction.

[0012] The balloon catheter 1 is configured so that fluid is supplied to the interior of the balloon 10 through the shaft 2, and the inflation and deflation of the balloon 10 can be controlled using an indeflator (a balloon pressurizer / depressurizer). The fluid may be pressurized fluid pressurized by a pump or the like. Hereinafter, the fluid supplied to the interior of the balloon 10 will be referred to as the "balloon inflation fluid."

[0013] The shaft 2 is composed of, for example, an inner shaft 3 and an outer shaft 4. The inner shaft 3 is disposed within the lumen of the outer shaft 4. The inner shaft 3 can function as a passage for a guide wire that guides the advancement of the shaft 2, and when the balloon catheter 1 is in use, the guide wire is inserted into the lumen of the inner shaft 3. The space between the inner shaft 3 and the outer shaft 4 can function as a flow path for the balloon inflation fluid.

[0014] In the rapid exchange type balloon catheter 1, a guidewire port 7 is provided midway from the distal side to the proximal side of the shaft 2, and the proximal end of the inner shaft 3 is connected to the guidewire port 7, and the distal end of the inner shaft 3 extends to the distal portion of the shaft 2, thereby forming a guidewire insertion passage extending from the guidewire port 7 to the distal portion of the shaft 2.

[0015] The outer shaft 4 may have a proximal outer shaft 4A and a distal outer shaft 4B. In this case, it is preferable that the inner shaft 3 is disposed in the lumen of the distal outer shaft 4B. The proximal outer shaft 4A and the distal outer shaft 4B may be made of the same material, or may be made of different materials. For example, it is preferable that the proximal outer shaft 4A is made of resin or metal, and the distal outer shaft 4B is made of resin. Note that the outer shaft 4 may not be divided into the proximal outer shaft 4A and the distal outer shaft 4B, but may be made of a single member, or the proximal outer shaft 4A and the distal outer shaft 4B may each be made of multiple tubular members.

[0016] A hub 5 is preferably provided on the proximal side of the shaft 2. The hub 5 preferably has a fluid injection section 6 that communicates with a flow path for balloon inflation fluid in the shaft 2. The balloon 10, shaft 2 (inner shaft 3, outer shaft 4), and hub 5 can be joined together using conventional joining means such as adhesives or thermal welding.

[0017] Although not shown in the drawings, the balloon catheter may be an over-the-wire type balloon catheter in which an inner shaft extends from the distal to the proximal end of the shaft and a guidewire insertion passage is formed from the distal to the proximal end of the shaft. In this case, a flow path for a balloon inflation fluid and a guidewire insertion passage provided in the shaft preferably extend to a hub, and the hub preferably has a fluid injection portion communicating with the flow path for the balloon inflation fluid and a treatment portion communicating with the guidewire insertion passage. Preferably, the hub has a bifurcated structure, with the fluid injection portion provided on one side and the treatment portion provided on the other side.

[0018] It is preferable that the outer surface of the shaft 2 is coated. In a rapid exchange type balloon catheter 1, it is preferable that the outer surface of one or both of the proximal outer shaft 4A and the distal outer shaft 4B is coated, and it is more preferable that the outer surfaces of both the proximal outer shaft 4A and the distal outer shaft 4B are coated. In an over-the-wire type balloon catheter, it is preferable that the outer surface of the outer shaft is appropriately coated.

[0019] The coating can be a hydrophilic coating or a hydrophobic coating depending on the purpose. The outer surface of the shaft 2 can be coated by immersing the shaft 2 in a hydrophilic or hydrophobic coating agent, applying a hydrophilic or hydrophobic coating agent to the outer surface of the shaft 2, or covering the outer surface of the shaft 2 with a hydrophilic or hydrophobic coating agent. The coating agent may contain drugs or additives.

[0020] Examples of hydrophilic coating agents include hydrophilic polymers such as polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, and methyl vinyl ether-maleic anhydride copolymers, as well as hydrophilic coating agents made from any combination of these.

[0021] Examples of hydrophobic coating agents include polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxyalkane (PFA), silicone oil, hydrophobic urethane resin, carbon coat, diamond coat, diamond-like carbon (DLC) coat, ceramic coat, and substances terminated with alkyl groups or perfluoroalkyl groups and having low surface free energy.

[0022] A distal tip 8 is preferably provided at the distal end of the balloon catheter 1. The distal tip 8 may be provided as a separate member from the inner shaft 3, on a more distal side than the distal end of the inner shaft 3, or the inner shaft 3 may extend distally beyond the distal end of the balloon 10, so that the distal end of the inner shaft 3 functions as the distal tip 8.

[0023] To enable confirmation of the position of the balloon 10 under X-ray fluoroscopy, a radiopaque marker 9 may be placed on the shaft 2 at the portion where the balloon 10 is located in the longitudinal direction. The radiopaque marker 9 may be placed, for example, on the inner shaft 3 placed inside the balloon 10, and is preferably placed at positions corresponding to both ends of the straight tube portion of the balloon 10, or may be placed at a position corresponding to the center of the straight tube portion of the balloon 10.

[0024] The balloon 10 has a longitudinal axis direction and a radial direction, and is formed in a cylindrical shape with openings on the proximal and distal sides. The radial direction of the balloon 10 refers to a direction perpendicular to the longitudinal axis direction, extending radially from the center of the balloon 10. The balloon 10 also has a circumferential direction, which is the direction along the outer periphery of the balloon 10 in an expanded state in a vertical cross section of the balloon 10 in the longitudinal axis direction.

[0025] As shown in Figures 4 and 5, the balloon 10 preferably has a straight tube section 13, a proximal tapered section 12 located proximal to the straight tube section 13, and a distal tapered section 14 located distal to the straight tube section 13 in the longitudinal direction. The straight tube section 13 is formed into a substantially cylindrical shape extending in the longitudinal direction and has the largest radial length (outer diameter) in the balloon 10. The proximal tapered section 12 is located proximal to the straight tube section 13 and connects to the proximal end of the straight tube section 13. The proximal tapered section 12 is formed so that its outer diameter decreases with increasing distance from the straight tube section 13. The distal tapered section 14 is located distal to the straight tube section 13 and connects to the distal end of the straight tube section 13. The distal tapered section 14 is formed so that its outer diameter decreases with increasing distance from the straight tube section 13. The balloon 10 preferably further has a proximal sleeve portion 11 located proximal to the proximal tapered portion 12 and a distal sleeve portion 15 located distal to the distal tapered portion 14. The proximal sleeve portion 11 is located proximal to the proximal tapered portion 12 and connects to the proximal end of the proximal tapered portion 12. The proximal sleeve portion 11 is formed in a substantially cylindrical shape. The distal sleeve portion 15 is located distal to the distal tapered portion 14 and connects to the distal end of the distal tapered portion 14. The distal sleeve portion 15 is formed in a substantially cylindrical shape.

[0026] By configuring the balloon 10 as described above, when the balloon 10 is inflated at a stricture, the straight tube portion 13 comes into sufficient contact with the stricture, facilitating treatment such as dilating the stricture. Furthermore, because the balloon 10 has the proximal tapered portion 12 and the distal tapered portion 14, the outer diameters of the proximal and distal ends of the balloon 10 can be reduced when the balloon 10 is deflated, thereby reducing the difference in level between the shaft 2 and the balloon 10, making it easier to insert the balloon 10 into a body cavity, a forceps channel of an endoscope, or a delivery catheter such as a guiding catheter.

[0027] In the distal portion of the shaft 2, the inner shaft 3 preferably extends distally beyond the distal end of the outer shaft 4, and the inner shaft 3 preferably extends through the interior space of the balloon 10 from the proximal sleeve portion 11 to the distal sleeve portion 15. The outer surface of the inner shaft 3 preferably joins to the inner surface of the distal sleeve portion 15 of the balloon 10, and the outer surface of the outer shaft 4 preferably joins to the inner surface of the proximal sleeve portion 11 of the balloon 10. By configuring the distal portion of the shaft 2 in this manner, balloon inflation fluid can be supplied to the interior space of the balloon 10 through the space between the inner shaft 3 and the outer shaft 4.

[0028] There is no particular limitation on the size of the balloon 10. The size of the balloon 10 can be appropriately set, for example, such that the length of the straight pipe portion 13 in the longitudinal direction is 4 mm to 400 mm, and the outer diameter of the straight pipe portion 13 is 1 mm to 30 mm.

[0029] The balloon 10 (particularly the balloon body 16) is preferably made of a resin, more preferably a thermoplastic resin. This facilitates the manufacturing of the balloon 10 by molding. Examples of resins that can be used to form the balloon 10 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 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 10. For example, among polyamide resins, nylon 12 and nylon 11 are preferred materials for the balloon 10. 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 10. Among these, polyether ester amide elastomers are preferably used from the viewpoints of high yield strength and good dimensional stability of the balloon 10.

[0030] The balloon 10 has ridges 21 on its outer surface. The ridges 21 provide the balloon 10 with a scoring function, allowing it to bite into the calcified stenosis and create cracks in the stenosis when inflated at a stenotic portion of a blood vessel. This allows the stenotic portion to be dilated while suppressing dissection of the vascular intima. It also allows the balloon 10 to withstand high pressures and prevent overexpansion when pressurized. The balloon 10 can also be used to treat stenoses and lesions in body cavities other than blood vessels, but the following description focuses on the application of the balloon 10 to vascular treatment.

[0031] The ribs 21 of the balloon 10 will be described in detail with reference to Figures 6 and 7. Figure 6 shows a vertical cross-section in the longitudinal direction of the straight pipe portion 13 of the balloon 10 at a location where the ribs 21 are provided, and Figure 7 shows an enlarged cross-section of the ribs 21 of the balloon 10. Figure 6 shows an example of the configuration of the straight pipe portion 13 of the balloon 10 shown in Figures 4 and 5 in a vertical cross-section in the longitudinal direction, in which the ribs 21 are provided at three locations around the circumferential direction of the straight pipe portion 13.

[0032] The balloon 10 has a balloon body 16, and ridges 21 are provided on the outer surface of the balloon body 16. The ridges 21 are provided so as to protrude radially outward from the outer surface of the balloon body 16. By providing the ridges 21 in the balloon 10, a ridge-present region 25 and a ridge-free region 26 are formed on the outer surface of the straight tube section 13. Note that, when discontinuities 24 are formed between the ridges 21 as shown in FIG. 5 , the ridge-present region 25 includes the portion where the ridges 21 are formed and the portion where the discontinuities 24 of the ridges 21 are formed.

[0033] The balloon body 16 is the portion of the balloon 10 excluding the ridges 21 that protrude radially outward. In a vertical cross section of the balloon 10 along its longitudinal axis, the balloon body 16 preferably has a substantially circular outer shape. In the straight tube section 13, the balloon body 16 preferably has a cylindrical outer surface. The ridge-present region 25 is composed of the balloon body 16 and the ridges 21, and the ridge-free region 26 is composed of the balloon body 16.

[0034] The outer surface of the straight tube section 13 is preferably formed flat in the streak-free region 26. For example, it is preferable that the outer surface of the straight tube section 13 is not formed with a recess in part of the streak-free region 26. This facilitates uniform inflation of the balloon 10 and facilitates the desired scoring function of the streak-free region 21. Note that the flat outer surface of the straight tube section 13 in the streak-free region 26 means that the streak-free region 26 has a shape in which a plane is curved in an arch shape, and no irregularities are formed in the curved plane. This irregularity does not include surface roughness that is unavoidable during manufacturing. The balloon 10 is preferably formed flat in the streak-free region 26 on the outer surfaces of the proximal tapered section 12 and the distal tapered section 14.

[0035] The ridges 21 have a peak 21A and a base 21B. The peak 21A is the tip of the ridge 21, i.e., the radially outermost part of the ridge 21, and the base 21B is the boundary with the balloon body 16, i.e., the radially innermost part of the ridge 21.

[0036] The ridges 21 can be made of, for example, a resin. If the ridges 21 are made of a resin, the balloon 10 having the ridges 21 can be manufactured by resin molding, facilitating manufacturing. In this case, the ridges 21 and the balloon main body 16 are preferably made of the same resin, and the ridges 21 and the balloon main body 16 are preferably integrally molded. The balloon main body 16 may have an inner layer and an outer layer. In this case, the ridges 21 are preferably made of the same resin as the outer layer of the balloon main body 16. This makes it less likely that the ridges 21 will unintentionally fall off the balloon main body 16. Alternatively, the ridges 21 and the balloon main body 16 may be made of different resins, as long as the resins making up the ridges 21 and the balloon main body 16 are compatible to a certain extent.

[0037] The ridges 21 may be made of metal, or a combination of metal and resin. In this case, it is preferable that the portions of the ridges 21 including the apexes 21A are made of metal. This makes it easier for the ridges 21 to create cracks in or incise the narrowed area when the balloon 10 is inflated. For example, the entire ridges 21 may be made of metal, or the portions of the ridges 21 including the bases 21B may be made of resin and the portions of the ridges 21 including the apexes 21A may be made of metal. Therefore, it is preferable that the ridges 21 be made of resin, metal, or a combination thereof.

[0038] The ridges 21 are provided on the outer surface of the balloon 10 so as to extend in a ridge-like pattern. The ridges 21 have an extension direction of the ridges 21 and a width direction perpendicular thereto. The ridges 21 are preferably provided so as to extend in the longitudinal axis direction of the balloon 10. In this case, the ridges 21 may extend substantially parallel to the longitudinal axis direction or may extend obliquely to the longitudinal axis direction. The ridges 21 may also extend spirally in the longitudinal axis direction of the balloon 10. Note that, from the viewpoints of improving the scoring function of the balloon 10 and facilitating the manufacture of a balloon 10 having the ridges 21, it is preferable that the ridges 21 extend substantially parallel to the longitudinal axis direction. The ridges 21 extending substantially parallel to the longitudinal axis direction preferably extend at an angle of ±10° or less with respect to the longitudinal axis direction, and more preferably at an angle of ±5° or less. In the balloon 10 shown in the drawings, the ridges 21 extend substantially parallel to the longitudinal axis of the balloon 10 , and the extending direction of the ridges 21 coincides with the longitudinal axis of the balloon 10 .

[0039] The ridges 21 are preferably provided at least on the straight tube section 13. This allows the ridges 21 to penetrate deeply into the stenotic portion of the blood vessel when the balloon 10 is inflated, thereby enhancing the scoring function of the ridges 21. In this case, the ridges 21 are preferably provided over 60% or more of the straight tube section 13 in the longitudinal direction, more preferably 70% or more, and even more preferably 80% or more. This allows cracks to be created over a wide area of ​​the stenotic portion when the balloon 10 is inflated. The ridges 21 may be provided over 90% or more of the straight tube section 13 in the longitudinal direction, or may be provided over almost the entire straight tube section 13 in the longitudinal direction. The ridges 21 may also be provided on the outer surfaces of the proximal tapered section 12 and / or the distal tapered section 14, or on the outer surfaces of the proximal sleeve section 11 and / or the distal sleeve section 15.

[0040] As shown in FIG. 5 , the balloon 10 may have interruptions 24 in the ridges 21. A balloon 10 with ridges 21 tends to have lower flexibility in the longitudinal direction compared to a balloon 10 without ridges 21. However, providing the interruptions 24 in the ridges 21 on the balloon 10 can improve the flexibility of the balloon 10 in the longitudinal direction. In this case, it is preferable that multiple ridges 21 are arranged in a row in the longitudinal direction, and that interruptions 24 are formed between the multiple ridges 21. At the interruptions 24, the balloon body 16 is exposed on the outer surface of the balloon 10. The number of multiple ridges 21 arranged in a row in the longitudinal direction may be two or more, three or more, or four or more. There is no particular upper limit to the number of multiple ridges 21 arranged in a row in the longitudinal direction, and it may be, for example, 20 or less, 15 or less, 10 or less, or 8 or less. When multiple convex ribs 21 are arranged in a line in the longitudinal axis direction, it is preferable that the proximal convex rib 21 and the distal convex rib 21 sandwiched between the interrupted portion 24 have substantially the same height and substantially the same width.

[0041] Only one or more ridges 21 may be provided in a vertical cross section in the longitudinal axis direction of the balloon 10. When only one ridge 21 is provided on the balloon 10, only one non-ridge region 26 is formed on the balloon 10, and when multiple ridges 21 are provided on the balloon 10, multiple non-ridge regions 26 are formed on the balloon 10. The same number of non-ridge regions 26 as the number of ridges 21 are formed.

[0042] It is preferable that multiple ridges 21 be provided at different circumferential positions in a cross section perpendicular to the longitudinal axis of the balloon 10. That is, it is preferable that the ridges 21 be provided at multiple locations around the circumference of the balloon 10. In this case, it is preferable that the ridges 21 be arranged at approximately equal intervals around the circumference of the balloon 10. This makes it possible to create cracks at multiple locations in the narrowed area when the balloon 10 is inflated. It is preferable that the ridges 21 be provided at two or more locations around the circumference of the balloon 10, more preferably three or more locations, and preferably twelve or fewer locations, more preferably ten or fewer locations, and even more preferably eight or fewer locations. In this case, it is preferable that the circumferential spacing between the ridges 21 be longer than the circumferential length of one ridge 21.

[0043] When the ribs 21 are provided at multiple locations around the circumference of the balloon 10, the above-described discontinuous portions 24 of the ribs 21 are preferably provided on each of the ribs 21. In this case, it is preferable that multiple ribs 21 are arranged in the longitudinal direction to form a group of ribs 21, and that the group of ribs 21 is provided at multiple locations around the circumference of the balloon 10.

[0044] The cross-sectional shape of the ridges 21 is not particularly limited. For example, the shape of the ridges 21 in a cross section perpendicular to the extension direction of the ridges 21 may be a polygon such as a triangle or a rectangle, a partial circle such as a semicircle or a sector, a wedge, a convex, a spindle, or an irregular shape. Polygons include polygons with clear corners and straight sides, as well as rounded polygons with rounded corners and polygons with at least some curved sides. Note that the ridges 21 are preferably formed so that their width gradually decreases toward the apex 21A.

[0045] In a cross section perpendicular to the extension direction of the ridges 21, the height of the ridges 21 is preferably at least 0.2 times the width (maximum width) of the ridges 21. Forming the ridges 21 in this manner allows the ridges 21 to more easily penetrate into the narrowed portion when the balloon 10 is inflated at the narrowed portion, thereby enhancing the scoring function of the ridges 21. The ridges 21 are preferably formed so that their width is at its maximum at the base 21B, thereby ensuring stable placement of the ridges 21 on the outer surface of the balloon body 16. The height of the ridges 21 is more preferably at least 0.4 times the width of the ridges 21, and even more preferably at least 0.7 times. Meanwhile, the height of the ridges 21 is preferably at most 2.0 times the width of the ridges 21, more preferably at most 1.8 times, and even more preferably at most 1.5 times. This facilitates ensuring the flexibility of the balloon 10 in the areas where the ridges 21 are present.

[0046] In the balloon 10, the thickness of the portion where the ridges 21 are provided, i.e., the ridge-presence region 25, is preferably thicker than the thickness of the portion where the ridges 21 are not provided, i.e., the ridge-free region 26. This enhances the scoring function of the ridges 21. The thickness (maximum thickness) of the ridge-presence region 25 is preferably 1.5 times or more, more preferably 2.0 times or more, and even more preferably 2.5 times or more, the thickness (maximum thickness) of the ridge-free region 26. There is no particular upper limit to the thickness of the ridge-presence region 25, and it may be, for example, 30 times or less, 20 times or less, or 10 times or less the thickness of the ridge-free region 26.

[0047] The balloon 10 may have an inner ridge (not shown) that protrudes radially inward on the inner surface of the balloon 10. The ridge 21 and the inner ridge may be located at the same position in the longitudinal or circumferential direction of the balloon 10, and are preferably integrally molded, which may allow a portion of the balloon 10 to be thick-walled.

[0048] The balloon 10 has a drug layer 31 provided on the end surface 22 of the ribs 21. Figures 8 and 9 show examples of the configuration of the ribs 21 in which the drug layer 31 is provided on the end surface 22. Figures 8 and 9 show cross-sectional views of the ribs 21 passing through the apex 21A of the ribs 21 along the extension direction of the ribs 21 and the radial direction of the balloon 10, showing examples of the configuration of the ribs 21 in which the cross-sectional shapes of the end surfaces 22 are different. The end surface 22 of the ribs 21 refers to the end surface of the ribs 21 in the extension direction, i.e., the surface facing the extension direction at the end of the ribs 21 in the extension direction, and refers to the surface visible when the ribs 21 are viewed from one side in the extension direction.

[0049] The balloon 10 has a drug layer 31 on the end surface 22 of the ribs 21. When the balloon 10 is inflated at a stenotic portion of a blood vessel, the ribs 21 penetrate the stenotic portion, effectively dilating the stenotic portion. Furthermore, the drug can be placed near the portion of the vascular wall where the ribs 21 penetrate. The drug placed in this manner gradually penetrates the vascular wall, rather than being supplied all at once. This can prevent, for example, the formation of an aneurysm due to drug overdose. Furthermore, because the drug is placed near the portion of the vascular wall where the ribs 21 penetrate and open, the drug can easily penetrate into the vascular wall through the open portion. This allows the drug to be delivered to the vascular wall in a sustained manner.

[0050] The drug layer 31 provided on the end surfaces 22 of the ridges 21 also facilitates reliable delivery of the drug to the surface of the blood vessel wall without dropping off during inflation of the balloon 10. Normally, the non-ridge regions 26 of the balloon 10 are folded before inflation, and the folds of the non-ridge regions 26 unfold during inflation. However, the drug layer 31 provided on the end surfaces 22 of the ridges 21 is less susceptible to the unfolding movement of the folds of the non-ridge regions 26 during inflation of the balloon 10. Therefore, compared with when the drug layer 31 is provided on the non-ridge regions 26 or on the side surfaces 23 of the ridges 21, the drug layer 31 provided on the end surfaces 22 of the ridges 21 is less likely to peel off from the surface of the balloon 10 during inflation of the balloon 10. As a result, reliable delivery of the drug to the surface of the blood vessel wall during inflation of the balloon 10 is facilitated.

[0051] The drug contained in drug layer 31 is not particularly limited as long as it is a pharmacologically active substance, and examples include medicaments acceptable as medicaments such as gene therapy drugs, non-gene therapy drugs, small molecules, and cells. In particular, when balloon catheter 1 is used for the purpose of suppressing restenosis of the blood vessel 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 of two or more types.

[0052] In addition to the pharmacologically active substance, the drug layer 31 may contain an auxiliary agent for improving the dispersibility, solubility, migration to the vascular wall, and storage stability of the drug. Examples of the auxiliary agent include a stabilizer, a binder, a disintegrant, a moisture-proofing agent, a preservative, and a dissolution aid. Specific examples include lactose, sucrose, maltose, dextrin, xylitol, erythritol, mannitol, ethylenediamine, potassium iodide, urea, polysorbate, dibutylhydroxytoluene, polyethylene glycol, lipids, sodium pyrosulfite, ascorbic acid, tocopherol, benzoic acid, parahydroxybenzoic acid esters, polyacrylic acid, polylactic acid, polyglycolic acid, hyaluronic acid, chitosan, and gelatin.

[0053] A protective layer may be provided on the outer surface of the drug layer 31 to prevent the drug from eluting or falling off into body fluids during delivery of the balloon 10 to the stricture site. The protective layer may be composed of, for example, a hydrophilic component. For example, when delivering the balloon 10 to a body cavity containing a body fluid rich in lipid-soluble components, such as a bile duct containing bile, a protective layer composed of a hydrophilic component provided on the outer surface of the drug layer 31 can prevent dissolution of the protective layer upon contact with body fluids, thereby enabling the protective layer to protect the drug layer 31. 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 may also be composed of a hydrophobic component. For example, when the balloon 10 is delivered into a body cavity containing a body fluid with a high water content, such as a blood vessel containing blood, if a protective layer made of a hydrophobic component is provided on the outer surface of the drug layer 31, dissolution of the protective layer upon contact with the body fluid is suppressed, and the protective layer can perform its protective function for the drug layer 31. 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.

[0054] Even when the balloon 10 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 is preferably made of the aforementioned hydrophilic component, particularly a high-molecular-weight hydrophilic polymer. Using a high-molecular-weight hydrophilic polymer as the protective layer can prevent dissolution of the protective layer due to the water content of the body fluid, thereby making it easier to maintain the protective function of the drug layer 31.

[0055] The drug constituting the drug layer 31 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 salts such as sugar, urea, and potassium iodide, ascorbic acid, polylactic acid, and polyglycolic acid. This increases the brittleness of the drug layer 31, making the drug layer 31 more likely to peel off from the outer surface of the balloon 10 when the balloon 10 is inflated. On the other hand, in order to enhance the protective function of the protective layer, the protective layer is preferably amorphous. Examples of components of an amorphous protective layer 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.

[0056] The end surface 22 of the ridge 21 has an apex 22A and a base 22B. In the end surface 22 of the ridge 21, the apex 22A refers to the radially outermost portion of the end surface 22, and is the end of the apex 21A of the ridge 21. In the end surface 22 of the ridge 21, the base 22B refers to the boundary with the balloon main body 16, i.e., the radially innermost portion of the end surface 22.

[0057] Each ridge 21 includes two end faces 22 in the extension direction of the ridge 21, and the drug layer 31 may be provided on at least one of the end faces 22 of the multiple ridges 21. The end faces 22 of each ridge 21 preferably have a proximal end face 22P and a distal end face 22D. The proximal end face 22P of the ridge 21 may extend distally from the base 22B toward the apex 22A, may extend proximally, or may extend radially. The distal end face 22D of the ridge 21 may extend proximally from the base 22B toward the apex 22A, may extend distally, or may extend radially. The proximal end face 22P and the distal end face 22D of the ridge 21 are preferably formed as described above in a cross section passing through the apex 21A of the ridge 21 and along the extension direction and radial direction of the ridge 21. The end face 22 of the ridge 21 may extend linearly from the base 22B to the apex 22A as shown in Fig. 8, or may extend curvedly from the base 22B to the apex 22A as shown in Fig. 9. In Fig. 9, the end face 22 of the ridge 21 is formed to be recessed, which allows the end face 22 to stably hold a larger amount of drug.

[0058] The drug layer 31 is preferably provided on the end surface 22 of the ridge 21 in the straight tube portion 13 of the balloon 10. In this case, it is preferable that at least a portion of the ridge 21 is located in the straight tube portion 13, and that the end surface 22 of the ridge 21 is located in the straight tube portion 13. The straight tube portion 13 of the balloon 10 is the portion of the balloon 10 that expands the most when the balloon 10 is inflated. Therefore, by providing the drug layer 31 on the end surface 22 of the ridge 21 in the straight tube portion 13 of the balloon 10, the drug layer 31 is pressed firmly against the surface of the blood vessel wall when the balloon 10 is inflated, making it easier to reliably deliver the drug to the surface of the blood vessel wall. Furthermore, the ridge 21 provided in the straight tube portion 13 can penetrate deeper into the blood vessel wall when the balloon 10 is inflated, making it easier for the drug to penetrate deep into the interior of the blood vessel wall.

[0059] The thickness of drug layer 31 at base 22B of end face 22 of ridge 21 is preferably greater than the thickness of drug layer 31 at apex 22A of end face 22 of ridge 21. If drug layer 31 is formed in this manner, when balloon 10 is inflated at a narrowed portion of a blood vessel, the amount of drug suddenly supplied to the inside of the blood vessel wall is reduced, making it easier to distribute the drug on the surface of the blood vessel wall. This prevents the drug from being partially overdosed inside the blood vessel wall.

[0060] The thickness of drug layer 31 at base 22B and apex 22A of end face 22 of ridge 21 can be determined by measuring the thickness of drug layer 31 formed on end face 22 in a cross section passing through apex 21A of ridge 21 along the extension direction and radial direction of ridge 21. The thickness of drug layer 31 at base 22B of end face 22 refers to the shortest distance from base 22B to the surface of drug layer 31 at end face 22 of ridge 21, i.e., the length from base 22B to the shortest point 32 on the surface of drug layer 31, and corresponds to the length indicated by arrow L1 in Figures 8 and 9. It is anticipated that cracks may occur on the surface of drug layer 31 due to its drying state. In such a case, the shortest distance to the surface of drug layer 31 excluding the location of the crack is defined as the thickness of drug layer 31 at base 22B of end face 22. The thickness of the drug layer 31 at the top 22A of the end surface 22 is 0 if the drug layer 31 is not present at the top 22A, and if the drug layer 31 is present at the top 22A, it means the shortest thickness of the drug layer 31 at the top 22A, i.e., the shortest distance from the top 22A to the surface of the drug layer 31.

[0061] As shown in Figure 10, the drug layer 31 may also be provided on the side surface 23 of the ridge 21. Figure 10 shows an example of the configuration of the ridge 21 in which the drug layer 31 is provided on the side surface 23 of the ridge 21, and shows a vertical cross-section of the ridge 21 in the longitudinal axis direction. The side surface 23 of the ridge 21 refers to the side surface in the width direction of the ridge 21. In this case, it is preferable that the thickness of the drug layer 31 at the base 21B of the ridge 21 on the side surface 23 of the ridge 21 is thicker than the thickness of the drug layer 31 at the top 21A of the ridge 21. This reduces the amount of drug that reaches the inside of the blood vessel wall at once when the balloon 10 is inflated at a stenotic portion of a blood vessel. Furthermore, the ridge 21 is more likely to bite into the stenotic portion, allowing the balloon 10 to effectively dilate the stenotic portion.

[0062] The thickness of drug layer 31 at base 21B and crest 21A of side surface 23 of ridge 21 can be determined by measuring the thickness of drug layer 31 formed on side surface 23 of ridge 21 in a vertical cross section in the longitudinal axis direction of balloon 10, in the same manner as the thickness of drug layer 31 at base 22B and crest 22A of end surface 22 of ridge 21 described above. Drug layer 31 does not have to be provided on side surface 23 of ridge 21. On side surface 23 of ridge 21, drug layer 31 is not provided, or drug layer 31 is provided so that the thickness of drug layer 31 at base 21B of ridge 21 is thicker than the thickness of drug layer 31 at crest 21A of ridge 21 over a range of preferably 60% or more of the extension direction of ridge 21, more preferably 70% or more, even more preferably 80% or more, and even more preferably 90% or more.

[0063] 11 to 13, it is preferable that the surface of drug layer 31 is formed with cracks 33 extending along bases 22B of end faces 22 of ridges 21. By forming cracks 33 in this way on the surface of drug layer 31, when drug layer 31 comes into contact with the inner surface of the blood vessel wall when balloon 10 is expanded at the stenosis site, drug layer 31 provided on end faces 22 of ridges 21 is likely to peel off from the surface of balloon 10 from cracks 33, making it easier for drug layer 31 to migrate from the surface of balloon 10 toward the blood vessel wall.

[0064] When viewed from the outside of the balloon 10, the cracks 33 are preferably formed on the surface of the drug layer 31 so as to extend along the base 22B of the end face 22, i.e., along the extension direction of the base 22B (see FIG. 11 ). The cracks 33 may be formed so as to extend parallel to the extension direction of the base 22B, or at least a portion of the cracks 33 may be formed so as to extend obliquely relative to the extension direction of the base 22B. It is sufficient that the cracks 33 as a whole extend along the extension direction of the base 22B of the end face 22. The cracks 33 may be formed so as to extend continuously along the base 22B, or may be formed so as to extend intermittently. Furthermore, at least a portion of the multiple cracks 33 extending along the base 22B may be formed side by side in the longitudinal axis direction.

[0065] 12 and 13 , in a cross section taken along the extension direction and radial direction of ridge 21, crack 33 is preferably formed at or near the closest point 32 on the surface of drug layer 31 from base 22B of end face 22 of ridge 21. Specifically, in a vertical cross section taken along the extension direction and radial direction of ridge 21, a straight line is drawn connecting base 22B of end face 22 of ridge 21 to closest point 32 on the surface of drug layer 31, and the length of the line from base 22B to closest point 32 is defined as R. In a cross section taken along the extension direction and radial direction of ridge 21, crack 33 on the surface of drug layer 31 is preferably located within an imaginary circle 34 having a radius of 1.5R and centered at base 22B. More preferably, in a cross section taken along the extension direction of ridge 21, crack 33 is preferably entirely contained within an imaginary circle 34 having a radius of 1.5R and centered at base 22B. 12 and 13, a part of an imaginary circle 34 having a radius of 1.5R and centered on the base portion 22B is shown by a dashed dotted line. The radius of the imaginary circle 34 is more preferably 1.3R.

[0066] In a cross section along the extension direction and radial direction of the convex rib 21, the crack 33 may be formed so as to extend from the surface of the drug layer 31 to the outer surface of the balloon 10, or may be formed so as to extend from the surface of the drug layer 31 to the interior of the drug layer 31 as its end point.

[0067] In the balloon 10, it is sufficient that the crack 33 is formed in the drug layer 31 along at least one of the bases 22B of the end faces 22 of the multiple ridges 21. When multiple ridges 21 are provided, it is preferable that the crack 33 is formed in the drug layer 31 along at least one of the bases 22B of the multiple end faces 22 of each ridge 21.

[0068] Cracks 33 in drug layer 31 can be formed, for example, by bending balloon 10 in the longitudinal direction after drug layer 31 is formed on end face 22 of ridge 21. In this case, balloon 10 is preferably bent in the longitudinal direction at or near the location of end face 22 of ridge 21 in the longitudinal direction.

[0069] When cracks 33 are formed on the surface of drug layer 31, the thickness of drug layer 31 at base 22B of end face 22 of ridge 21 means the thickness of drug layer 31 excluding the location where crack 33 is formed. In other words, the thickness of drug layer 31 at base 22B of end face 22 is the length of a straight line drawn from base 22B to shortest point 32 on end face 22 of ridge 21, and shortest point 32 is measured from base 22B to the shortest point on the surface of drug layer 31 excluding the location where crack 33 is formed.

[0070] As shown in Figure 14, a protective layer 35 may be provided on the outer surface of the drug layer 31, and the protective layer 35 may be provided to cover at least a portion of the cracks 33. Figure 14 shows an example of a configuration in which the protective layer 35 is provided on the outer surface of the drug layer 31 so as to cover the cracks 33 in the cross-sectional view of the ridges 21 shown in Figure 12. By providing the protective layer 35 on the outer surface of the drug layer 31 so as to cover at least a portion of the cracks 33, it is possible to prevent bodily fluids from entering the cracks 33 during delivery of the balloon 10 to the stenotic area, which could cause the drug layer 31 to fall off or the drug to elute from the drug layer 31. The protective layer 35 is preferably provided on the outer surface of the drug layer 31 so as to cover the entire cracks 33. It is also preferable that the protective layer 35 be provided so as to penetrate into the cracks 33 and fill at least a portion of the cracks 33.

[0071] 10 , when drug layer 31 is also provided on side surface 23 of ridge 21, cracks may be formed in drug layer 31 provided on side surface 23 of ridge 21 along base 21B of side surface 23 of ridge 21 (not shown). In this case, it is preferable that the cracks be formed on the surface of drug layer 31 so as to extend along the extending direction of base 21B, i.e., along the extending direction of the boundary between ridge-present region 25 and ridge-free region 26, when balloon 10 is viewed from the outside.

[0072] As shown in Fig. 5, it is preferable that a plurality of ridges 21 are arranged in the longitudinal direction, with interruptions 24 formed between the plurality of ridges 21, and as shown in Fig. 15 and Fig. 16, it is preferable that drug layer 31 is provided on end surface 22 of ridges 21 facing interruptions 24. Figs. 15 and 16 show configuration examples in which drug layer 31 is provided on end surface 22 of ridges 21 facing interruptions 24. Figs. 15 and 16 show examples of ridges 21 whose end surfaces 22 have different cross-sectional shapes, and show cross sections of ridges 21 passing through apex 21A of ridges 21 along the longitudinal axis and radial directions.

[0073] By providing drug layer 31 on end face 22 of ridge 21 facing discontinuity 24, drug layer 31 is less likely to fall off end face 22 of ridge 21 when balloon 10 is delivered to a treatment target site such as a stricture, and drug layer 31 is more likely to be stably held on end face 22 of ridge 21. In this case, drug layer 31 is preferably provided on both end faces 22 of ridge 21 that sandwich discontinuity 24; that is, drug layer 31 is preferably provided on both distal end face 22D of ridge 21 adjacent to the proximal side of discontinuity 24 and proximal end face 22P of ridge 21 adjacent to the distal side of discontinuity 24.

[0074] When the balloon 10 has multiple interruptions 24 in the ridges 21, it is preferable that a drug layer 31 be provided in at least one of the multiple interruptions 24, more preferably that a drug layer 31 be provided in at least half of the interruptions 24, even more preferably that a drug layer 31 be provided in at least three-quarters of the interruptions 24, and particularly preferably that a drug layer 31 be provided in all of the interruptions 24.

[0075] In a plurality of ridges 21 arranged in a line in the longitudinal direction, the length of the interrupted portions 24, specifically the longitudinal separation distance between the base 22B of the distal end face 22D of the ridge 21 adjacent to the proximal side of the interrupted portion 24 and the base 22B of the proximal end face 22P of the ridge 21 adjacent to the distal side of the interrupted portion 24, is preferably shorter than the longitudinal length of each ridge 21. In a plurality of ridges 21 arranged in a line in the longitudinal direction, the length of the interrupted portions 24 is preferably 0.5 times or less, more preferably 0.3 times or less, and even more preferably 0.2 times or less, the average longitudinal length of each ridge 21. This makes it easier to ensure the scoring function of the ridges 21. There is no particular lower limit on the length of the interrupted portions 24, and the length of the interrupted portions 24 may be zero. For example, when viewed from the side of the convex rib 21, the interrupted portion 24 may be formed in a V-shape, in which case the length of the interrupted portion 24, i.e., the longitudinal distance between the base 22B of the distal end face 22D of the convex rib 21 adjacent to the proximal side of the interrupted portion 24 and the base 22B of the proximal end face 22P of the convex rib 21 adjacent to the distal side of the interrupted portion 24, is zero.

[0076] The length of the interrupted portion 24 may be greater than zero. In this case, the base 22B of the distal end surface 22D of the ridge 21 adjacent to the proximal side of the interrupted portion 24 is spaced apart in the longitudinal direction from the base 22B of the proximal end surface 22P of the ridge 21 adjacent to the distal side of the interrupted portion 24. The length of the interrupted portion 24 may be 0.01 times or more, 0.03 times or more, 0.05 times or more, or 0.1 times or more the average length of each ridge 21 in the longitudinal direction. Alternatively, the length of the interrupted portion 24 in the longitudinal direction may be 0.1 times or more, 0.3 times or more, or 0.5 times or more the height of the ridge 21 adjacent to the proximal or distal side of the interrupted portion 24. If the interrupted portion 24 is formed to a predetermined length in the longitudinal direction, it is possible for the interrupted portion 24 to hold a larger amount of drug. The longitudinal length of the interrupted portion 24 may be 5 times or less, 3 times or less, or 2 times or less the height of the ridge 21 adjacent to the proximal or distal side of the interrupted portion 24, which makes it easier to ensure the scoring function of the balloon 10.

[0077] The discontinuous portions 24 of the ridges 21 are preferably formed at least in the straight tube portion 13 of the balloon 10 (see FIG. 5 ). A balloon 10 provided with ridges 21 tends to have higher rigidity in the areas where the ridges 21 are provided. Therefore, a balloon 10 provided with ridges 21 is more likely to have reduced flexibility in the longitudinal direction compared to a balloon 10 without ridges 21. For example, in a shunt formed during hemodialysis, blood vessels bend significantly at the arteriovenous anastomosis. Passing a balloon through such an area may be difficult if the balloon is provided with ridges. Alternatively, a balloon for lower limbs may be inserted through the iliac artery during treatment, but the blood vessels bend significantly at the bifurcation where the left and right iliac arteries branch off from the abdominal aorta. Therefore, if a balloon for lower limbs is provided with ridges, it may be difficult to pass the balloon from one iliac artery to the other. In particular, since balloons for lower limbs are long, there is a high risk that the balloon will not be able to pass through areas of blood vessels with large bends. However, if the straight tube portion 13 of the balloon 10 has the discontinuous portion 24 of the ribs 21 formed therein, the flexibility of the balloon 10 in the longitudinal direction can be improved.

[0078] When the straight tube section 13 is divided into three equal parts in the longitudinal direction into a proximal section 17, an intermediate section 18, and a distal section 19, the discontinuous portions 24 of the ridges 21 may be provided in any of the proximal section 17, the intermediate section 18, and the distal section 19. In one embodiment, the discontinuous portions 24 are preferably provided in the distal section 19 of the straight tube section 13. By providing the discontinuous portions 24 of the ridges 21 in this manner, the flexibility of the distal portion of the balloon 10 (specifically, the distal section 19 of the straight tube section 13) can be improved. In this case, the discontinuous portions 24 are preferably provided in the distal section 19 of each ridge 21 provided in the straight tube section 13.

[0079] The discontinuous portion 24 is also preferably provided in the proximal section 17 of the straight tube portion 13. This increases the flexibility of the proximal portion of the balloon 10 (specifically, the proximal section 17 of the straight tube portion 13), and improves the insertability of the balloon 10 through the curved portion when the balloon 10 is pulled back and passed through a curved portion of a blood vessel or the like after treatment with the balloon 10. In this case, the discontinuous portion 24 is preferably provided in the proximal section 17 of each ridge 21 provided on the straight tube portion 13.

[0080] The discontinuous portion 24 does not have to be provided in the intermediate section 18 of the straight tube section 13. Providing the ridges 21 in this manner makes it easier to impart a high scoring function to the balloon 10 while improving the flexibility of the balloon 10. On the other hand, to further improve the flexibility of the balloon 10, the discontinuous portion 24 may be provided in the intermediate section 18 of the straight tube section 13. For example, since a balloon 10 for use in the lower limbs has a long length in the longitudinal direction, providing the discontinuous portion 24 in the intermediate section 18 ensures the flexibility of the balloon 10 in the longitudinal direction even for a balloon 10 with a long length in the longitudinal direction, and also allows a larger amount of drug to be retained in the discontinuous portion 24.

[0081] 15 and 16 , in interruptions 24, drug layer 31 is preferably provided so as to connect both end faces 22 of ridge 21 that sandwich interruption 24, and drug layer 31 is preferably formed in this manner in at least one interruption 24. Therefore, interruptions 24 preferably include a specific interruption 24 provided with drug layer 31 that satisfies the following requirement A: (Requirement A) Drug layer 31 is provided from distal end face 22D of ridge 21 adjacent to the proximal side of the specific interruption 24 to proximal end face 22P of ridge 21 adjacent to the distal side of the specific interruption 24.

[0082] The specific discontinuities 24 provided with the drug layer 31 that satisfies the above requirement A are able to retain a larger amount of drug, allowing a larger amount of drug to be delivered to the surface of the blood vessel wall when the balloon 10 is inflated. Furthermore, the balloon 10 is flexible in the longitudinal direction, and if the drug layer 31 is provided so as to satisfy the above requirement A, bending the balloon 10 in the longitudinal direction makes it easier to deliver the drug retained in the specific discontinuities 24 to the surface of the blood vessel wall.

[0083] When drug layer 31 is provided as described above, drug layer 31 may be provided so as to fill the entire specific discontinuity 24, or so as to fill only a portion of specific discontinuity 24. For example, the thickness of drug layer 31 at the center of specific discontinuity 24 in the longitudinal direction may be 0.1 times or more, 0.2 times or more, 0.3 times or more, or 0.5 times or more the height of ridge 21 adjacent to the proximal or distal side of specific discontinuity 24. The thickness of the drug layer 31 at the center of the longitudinal direction of a particular interrupted portion 24 means the radial length of the drug layer 31 at the midpoint between the base 22B of the distal end face 22D of the convex rib 21 adjacent to the proximal side of the interrupted portion 24 and the base 22B of the proximal end face 22P of the convex rib 21 adjacent to the distal side of the interrupted portion 24, in a cross section passing through the apex 21A of the convex rib 21 along the longitudinal direction and the radial direction, and corresponds to the length indicated by arrow L2 in Figures 15 and 16.

[0084] In discontinuous portions 24, the surface of drug layer 31 may be recessed radially inward in a cross section passing through apex 21A of ridge 21 along the longitudinal axis and the radial direction. In this case, drug layer 31 may be formed in this manner in at least one discontinuous portion 24. For example, discontinuous portions 24 may include a specific discontinuous portion 24 provided with drug layer 31 that satisfies the following requirement B. (Requirement B) In a cross section passing through apex 21A of ridge 21 along the longitudinal axis and the radial direction, the thickness of drug layer 31 at base 22B of distal end face 22D of ridge 21 adjacent to the proximal side of the specific discontinuous portion 24 and the thickness of drug layer 31 at base 22B of proximal end face 22P of ridge 21 adjacent to the distal side of the specific discontinuous portion 24 are greater than the thickness of drug layer 31 at the center of the specific discontinuous portion 24 along the longitudinal axis.

[0085] If drug layer 31 is provided so as to satisfy requirement B above, drug layer 31 can be stably held in specific interruption 24. Therefore, drug layer 31 is less likely to fall off from specific interruption 24. The thickness of drug layer 31 at base 22B of distal end face 22D of ridge 21 adjacent to the proximal side of specific interruption 24 and the thickness of drug layer 31 at base 22B of proximal end face 22P of ridge 21 adjacent to the distal side of specific interruption 24, i.e., the thickness of drug layer 31 at base 22B of end face 22 of ridge 21 facing specific interruption 24, is, for example, preferably 1.1 times or more, more preferably 1.2 times or more, even more preferably 1.3 times or more, and preferably 5.0 times or less, more preferably 4.0 times or less, and even more preferably 3.0 times or less, of the thickness of drug layer 31 at the center of specific interruption 24 in the longitudinal direction. This allows drug layer 31 to be formed with an appropriate thickness both on specific discontinuities 24 and on end surfaces 22 of ridges 21 facing specific discontinuities 24. The thickness of drug layer 31 at bases 22B of end surfaces 22 of ridges 21 facing specific discontinuities 24 corresponds to the length indicated by arrow L1 in Figures 15 and 16 .

[0086] When the drug layer 31 is provided so as to satisfy the above requirement B, the thickness of the drug layer 31 at the center of the longitudinal axis of the specific interruption 24 is not particularly limited, and may be, for example, 0.7 times or less, 0.5 times or less, or 0.3 times or less the height of the convex rib 21 adjacent to the proximal or distal side of the specific interruption 24.

[0087] On the outer surface of the balloon 10, a drug layer 31 may also be provided in the non-ridge regions 26, or the drug layer 31 may not be provided in the non-ridge regions 26. If a drug layer 31 is provided in the non-ridge regions 26, a greater amount of drug can be delivered to the narrowed portion of the blood vessel by the balloon 10. Figure 17 shows a cross-sectional view taken along the line XVII-XVII of the discontinuities 24 of the ridges 21 shown in Figure 15 (however, only the cross-section of the drug layer 31 is shown). As shown in Figure 17, the drug layer 31 is preferably thicker in the discontinuities 24 than in the non-ridge regions 26, and it is preferable that the drug layer 31 be formed in this manner in at least one discontinuity 24. Therefore, the discontinuities 24 preferably include a specific discontinuity 24 provided with a drug layer 31 that satisfies requirement C below. (Requirement C) The outer surface of the balloon 10 is divided circumferentially into a region 25 with ridges and a region 26 without ridges, and in a cross section perpendicular to the longitudinal axis direction passing through the center of the longitudinal axis of a specific interruption 24, the average thickness of the drug layer 31 in the specific interruption 24 is thicker than the average thickness of the drug layer 31 in the region 26 without ridges.

[0088] The specific discontinuities 24 provided with the drug layer 31 satisfying the above requirement C are able to retain a larger amount of drug. By retaining the drug in this manner, a larger amount of drug can be placed near the ruptured portion of the surface of the blood vessel wall where the ridges 21 have dug into it when the balloon 10 is inflated. As a result, a larger amount of drug can be delivered to the interior of the blood vessel wall in a sustained manner. The average thickness of the drug layer 31 in the specific discontinuities 24 is preferably at least 1.2 times, more preferably at least 1.3 times, and even more preferably at least 1.5 times, the average thickness of the drug layer 31 in the non-ridge regions 26. The upper limit of the ratio of the average thickness of the drug layer 31 in the specific discontinuities 24 to the average thickness of the drug layer 31 in the non-ridge regions 26 is not particularly limited, and the average thickness of the drug layer 31 in the non-ridge regions 26 may be zero. In addition, since it is preferable to provide a drug layer 31 also in the non-protruding region 26, the average thickness of the drug layer 31 in the specific discontinuity 24 is preferably 30 times or less, more preferably 20 times or less, and even more preferably 10 times or less, the average thickness of the drug layer 31 in the non-protruding region 26.

[0089] The average thickness of the drug layer 31 at the specific discontinuities 24 and the average thickness of the drug layer 31 at the non-convex streak regions 26, as required by requirement C, can be determined, for example, as follows: The balloon 10 is cut perpendicular to the longitudinal axis at a position passing through the center of the specific discontinuities 24 in the longitudinal axis direction. While the balloon body 16 is maintained in a substantially circular state, the area of ​​the drug layer 31 at the specific discontinuities 24 and the circumferential length of the specific discontinuities 24, as well as the area of ​​the drug layer 31 at the non-convex streak regions 26 and the circumferential length of the non-convex streak regions 26, are measured. The average thickness of each drug layer 31 can be determined from the measured areas and circumferential lengths. The circumferential length of the specific discontinuities 24 corresponds to the circumferential length of the non-convex streak regions 25. The area of ​​each drug layer 31 can be easily determined by cutting the balloon 10 perpendicular to the longitudinal axis, photographing the cross-section, and processing the image.

[0090] Even when drug layer 31 is provided on end face 22 of ridge 21 facing discontinuity 24, cracks 33 may be formed in the surface of drug layer 31. Figures 18 and 19 show configuration examples in which cracks 33 are formed in the surface of drug layer 31 provided on end face 22 of ridge 21 facing discontinuity 24 in discontinuity 24 shown in Figures 15 and 16. Figure 20 shows a perspective view of ridge 21 in which drug layer 31 is provided on discontinuity 24 as shown in Figure 18.

[0091] Cracks 33 in drug layer 31 provided on end surfaces 22 of ridges 21 facing discontinuities 24 are preferably formed to extend along bases 22B of end surfaces 22 of ridges 21. If drug layer 31 is provided on end surfaces 22 of ridges 21 facing discontinuities 24 and cracks 33 extending along bases 22B of end surfaces 22 are formed on the surface of drug layer 31, drug layer 31 is less likely to fall off end surfaces 22 of ridges 21 when balloon 10 is delivered to a treatment site such as a stenosis, and drug layer 31 is stably held on end surfaces 22 of ridges 21. When balloon 10 is inflated at the stenosis, drug layer 31 on end surfaces 22 of ridges 21 comes into contact with the inner surface of the blood vessel wall, and drug layer 31 provided on end surfaces 22 of ridges 21 is likely to peel off from the surface of balloon 10 starting from cracks 33, facilitating migration of drug layer 31 from the surface of balloon 10 toward the blood vessel wall.

[0092] When drug layer 31 is provided in discontinuous portion 24 and cracks 33 are formed on the surface of drug layer 31, requirement A described above is satisfied as long as drug layer 31 satisfies requirement A except for the portion where cracks 33 are formed, and for example, it can be considered that the drug is present even in cracks 33. The same applies to requirement C above and various other configurations of drug layer 31.

[0093] As shown in Figure 21, a protective layer 35 may be provided on the outer surface of drug layer 31 provided in discontinuous portion 24, and protective layer 35 may be provided to cover at least a portion of crack 33. Figure 21 shows a configuration example in which protective layer 35 is provided on the outer surface of drug layer 31 so as to cover crack 33 in the cross-sectional view of balloon 10 shown in Figure 18. Protective layer 35 is preferably provided so as to penetrate into crack 33 and at least partially fill crack 33.

[0094] The end faces 22 of the ridges 21 may be recessed. For example, as shown in Figures 9, 16, and 19, the end faces 22 of the ridges 21 may be recessed radially inward in a cross section passing through the apex 21A of the ridges 21 and taken along the extending direction and radial direction of the ridges 21. Specifically, in a cross section passing through the apex 21A of the ridges 21 and taken along the extending direction and radial direction of the ridges 21, at least a portion of the proximal end face 22P of the ridges 21 may be located distal to an imaginary line connecting the apex 22A and base 22B of the proximal end face 22P of the ridges 21, and at least a portion of the distal end face 22D of the ridges 21 may be located proximal to an imaginary line connecting the apex 22A and base 22B of the distal end face 22D of the ridges 21. If the end faces 22 of the ridges 21 are formed in this manner, a greater amount of drug can be stably held on the end faces 22 of the ridges 21. Preferably, the entire proximal end face 22P of the ridges 21 is located distal to an imaginary line connecting the apex 22A and base 22B of the proximal end face 22P of the ridges 21, and the entire distal end face 22D of the ridges 21 is located proximal to an imaginary line connecting the apex 22A and base 22B of the distal end face 22D of the ridges 21. The discontinuous portions 24 of the ridges 21 are preferably formed so as to have a U-shaped outer edge in a cross section passing through the apex 21A of the ridges 21 and taken along the longitudinal axis and radial directions.

[0095] The end faces 22 of the ribs 21 may be recessed radially inward in a cross section perpendicular to the extension direction of the ribs 21. Figure 22 shows an example of a perspective view of the ribs 21 having end faces 22 formed in this manner. The drug layer 31 is omitted from Figure 22. In Figure 22, the end faces 22 of the ribs 21 can also be seen to be recessed in a cross section along the extension direction and circumferential direction of the ribs 21. Specifically, at least a portion of the distal end face 22D of the ribs 21 is recessed proximally, and at least a portion of the proximal end face 22P of the ribs 21 is recessed distally. Even when the end faces 22 of the ribs 21 are formed in this manner, a large amount of drug can be stably held by the end faces 22 of the ribs 21. The end face 22 of the convex rib 21 may be formed to be recessed radially inward in both a cross section passing through the top 21A of the convex rib 21 along the extension direction and radial direction of the convex rib 21 and a cross section perpendicular to the extension direction of the convex rib 21.

[0096] In the ridges 21 described above, the distal end face 22D of the ridges 21 adjacent to the proximal side of the interrupted portion 24 is formed to extend proximally from the base 22B of the ridges 21 toward the apex 21A, and the proximal end face 22P of the ridges 21 adjacent to the distal side of the interrupted portion 24 is formed to extend distally from the base 22B toward the apex 22A, but the interrupted portion 24 may include a specific interrupted portion 24 provided with a drug layer 31 that satisfies the following requirement D, as shown in Figures 23 and 24. Figures 23 and 24 show examples of the configuration of the specific interrupted portion 24, and show cross-sectional views passing through the apex 21A of the ridges 21 along the longitudinal axis and radial directions. (Requirement D) In ​​a cross section passing through the apex 21A of the ridge 21 along the longitudinal axis direction and the radial direction, the distal end face 22D of the ridge 21 adjacent to the proximal side of a specific interruption 24 has a portion extending radially from the base 22B of the end face 22D toward the apex 22A and / or a portion extending toward the distal side, and the proximal end face 22P of the ridge 21 adjacent to the distal side of a specific interruption 24 has a portion extending radially from the base 22B of the end face 22P toward the apex 22A and / or a portion extending toward the proximal side.

[0097] In Fig. 23, the distal end face 22D of the ridge 21 adjacent to the proximal side of a particular interruption 24 has a portion extending distally from the base 22B of the end face 22D toward the apex 22A, and the proximal end face 22P of the ridge 21 adjacent to the distal side of a particular interruption 24 has a portion extending proximally from the base 22B of the end face 22P toward the apex 22A. In Fig. 24, the distal end face 22D of the ridge 21 adjacent to the proximal side of a particular interruption 24 has a portion extending radially from the base 22B of the end face 22D toward the apex 22A and a portion extending distally, and the proximal end face 22P of the ridge 21 adjacent to the distal side of a particular interruption 24 has a portion extending radially from the base 22B of the end face 22P toward the apex 22A and a portion extending proximally. If a specific discontinuity 24 is formed in this manner, when the balloon 10 is inflated, a larger portion of the apex 21A of the ridge 21 comes into contact with the blood vessel wall, thereby enabling the ridge 21 to exert its scoring function more effectively.

[0098] As shown in Figure 24, the distal end face 22D of the convex rib 21 adjacent to the proximal side of a particular interruption 24 may have a portion extending proximally from the base 22B of the end face 22D toward the apex 22A, and the proximal end face 22P of the convex rib 21 adjacent to the distal side of a particular interruption 24 may have a portion extending distally from the base 22B of the end face 22P toward the apex 22A. Furthermore, it is preferable that the distal end face 22D of the convex rib 21 adjacent to the proximal side of a particular interruption 24 has a portion extending radially from the base 22B of the end face 22D toward the apex 22A and / or a portion extending toward the distal side that occupies a larger proportion of the height of the convex rib 21, and it is preferable that the proximal end face 22P of the convex rib 21 adjacent to the distal side of a particular interruption 24 has a portion extending radially from the base 22B of the end face 22P toward the apex 22A and / or a portion extending toward the proximal side that occupies a larger proportion of the height of the convex rib 21. Specifically, the radial length of the portion of the distal end face 22D of the ridge 21 adjacent to the proximal side of the specific discontinuity 24 that extends radially from the base 22B of the end face 22D toward the apex 22A and / or that extends distally is preferably 50% or more, more preferably 60% or more, even more preferably 70% or more, and even more preferably 80% or more of the radial length of the end face 22D. The radial length of the portion of the proximal end face 22P of the ridge 21 adjacent to the distal side of the specific discontinuity 24 that extends radially from the base 22B of the end face 22P toward the apex 22A and / or that extends proximally is preferably 50% or more, more preferably 60% or more, even more preferably 70% or more, and even more preferably 80% or more of the radial length of the end face 22P.

[0099] The specific interruptions 24 are provided with a drug layer 31. The provision of the drug layer 31 facilitates reliable delivery of the drug to the surface of the blood vessel wall without the drug falling off during delivery of the balloon 10 to a treatment site, such as a stenosis. The drug layer 31 provided at the specific interruptions 24 is protected by the distal end surface 22D of the ridge 21 adjacent to the proximal side of the specific interruptions 24 and the proximal end surface 22P of the ridge 21 adjacent to the distal side of the specific interruptions 24. Therefore, even if the surface of the balloon 10 comes into contact with the blood vessel wall during delivery of the balloon 10 to the treatment site, the drug layer 31 is less likely to fall off from the specific interruptions 24. Meanwhile, the drug layer 31 provided at the specific interruptions 24 is pushed up from the radially inner side by the balloon body 16 when the balloon 10 is inflated, allowing it to be delivered to the surface of the blood vessel wall.

[0100] The distal end face 22D of the ridge 21 adjacent to the proximal side of the specific interruption 24 formed as described above and the proximal end face 22P of the ridge 21 adjacent to the distal side of the specific interruption 24 may be recessed as shown in FIG. 25 . Specifically, the distal end face 22D of the ridge 21 adjacent to the proximal side of the specific interruption 24 may be recessed proximally in a cross section taken along the outer surface of the balloon body 16, and the proximal end face 22P of the ridge 21 adjacent to the distal side of the specific interruption 24 may be recessed distally in a cross section taken along the outer surface of the balloon body 16. The cross section taken along the outer surface of the balloon body 16 refers to a cross section of the ridge 21 cut along a plane parallel to the outer surface of the balloon body 16, and refers to a cross section taken along the longitudinal axis and circumferential directions of the balloon 10. Note that the drug layer 31 is omitted from FIG. 25 . In this manner, if the distal end face 22D of the convex rib 21 adjacent to the proximal side of the specific interruption 24 and / or the proximal end face 22P of the convex rib 21 adjacent to the distal side of the specific interruption 24 are formed, a greater amount of drug can be stably held in the specific interruption 24.

[0101] When the distal end face 22D of the ridge 21 adjacent to the proximal side of the specific interruption 24 has a portion extending radially from the base 22B of the end face 22D toward the apex 22A and / or a portion extending distally, and the proximal end face 22P of the ridge 21 adjacent to the distal side of the specific interruption 24 has a portion extending radially from the base 22B of the end face 22P toward the apex 22A and / or a portion extending proximally, a portion of the distal end face 22D of the ridge 21 adjacent to the proximal side of the specific interruption 24 may be in contact with a portion of the proximal end face 22P of the ridge 21 adjacent to the distal side of the specific interruption 24 (not shown). When the specific interruption 24 is formed in this manner, the scoring function of the ridge 21 can be more effectively achieved. In this case, it is preferable that at least a portion of the radially outer half of the distal end face 22D of the convex rib 21 adjacent to the proximal side of a particular interruption 24 contacts at least a portion of the radially outer half of the proximal end face 22P of the convex rib 21 adjacent to the distal side of a particular interruption 24.

[0102] In a vertical cross section of the balloon 10 along the longitudinal axis, the ridges 21 are preferably formed so that they have a portion that narrows toward the apex 21A, but do not have a portion that widens toward the apex 21A. This enhances the scoring function of the ridges 21. As shown in FIG. 26, the ridges 21 may be formed so that their width narrows stepwise toward the apex 21A. In this case, it is sufficient that at least a portion of the ridge 21 extending from the base 21B to the apex 21A has a portion that narrows stepwise toward the apex 21A. In FIG. 26, the ridges 21 are formed so that their width narrows stepwise toward the apex 21A, with a first step 29 adjacent to the outer surface of the balloon body 16 and a second step 30 closer to the apex 21A.

[0103] When end face 22 of rib projection 21 is formed in a multi-step configuration, crack 33 may be formed on the surface of drug layer 31 along the base of any step of end face 22 of multi-step rib projection 21. Figure 27 shows a cross-section of rib projection 21 having the cross-sectional shape shown in Figure 26, passing through apex 21A of rib projection 21 along the extending direction and radial direction of rib projection 21. In Figure 27, rib projection 21 is formed in a stepped shape in a cross section perpendicular to the extending direction of rib projection 21, and end face 22 is formed in a stepped shape in a cross section passing through apex 21A of rib projection 21 along the extending direction and radial direction of rib projection 21. Figure 27 shows an example in which crack 33 is formed on the surface of drug layer 31, extending along base 30B of second step portion 30 of end face 22 of rib projection 21. In this case, when the balloon 10 is inflated at the stenosis site and the drug layer 31 comes into contact with the inner surface of the blood vessel wall, the drug layer 31 provided on the end face 22 of the ridge 21 is likely to peel off from the surface of the balloon 10 starting from the crack 33, and the drug layer 31 is likely to migrate from the surface of the balloon 10 toward the blood vessel wall. The end face 22 of the multi-step ridge 21 may face the discontinuous portion 24.

[0104] In the balloon 10, it is preferable that the surface free energy E1 of the material constituting the surface of the ridges 21 be different from the surface free energy E2 of the material constituting the outer surface of the balloon main body 16. Surface free energy affects wettability and compatibility with liquids; the higher the surface free energy, the better the compatibility with liquids, and the lower the surface free energy, the more likely the material is to repel liquids. The drug layer 31 can be formed, for example, by coating the surface of the balloon 10 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 the ridges 21 and the surface free energy E2 of the material constituting the outer surface of the balloon main body 16, the drug layer 31 can be selectively provided at desired locations on the surface of the balloon 10.

[0105] The surface free energy E1 of the material constituting the surface of the ridge 21 and the surface free energy E2 of the material constituting the outer surface of the balloon body 16 can be determined by measuring the contact angle of a droplet of each material in the gas phase or the contact angle of an air bubble in the liquid phase. The contact angle can be measured using a commercially available contact angle meter, and the surface free energy can be calculated from the contact angle measurement results.

[0106] The surface free energy E1 of the material constituting the surface of the ridges 21 is preferably greater than the surface free energy E2 of the material constituting the outer surface of the balloon body 16. By setting the surface free energies of the materials constituting the surface of the ridges 21 and the outer surface of the balloon body 16 in this manner, the drug solution becomes more easily intimately attached to the surface of the ridges 21, making it easier to form a thicker drug layer 31 on the surface of the ridges 21.

[0107] The surface free energy E2 of the material constituting the outer surface of the balloon body 16 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 body 16, the chemical solution is likely to remain sufficiently on the outer surface of the balloon body 16.

[0108] The surface free energy E1 of the material constituting the surface of the ridges 21 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 16. Setting the surface free energy E1 of the material constituting the surface of the ridges 21 in this manner makes it easier to form a thicker drug layer 31 around the ridges 21. There is no particular upper limit to the ratio of the surface free energy E1 to the surface free energy E2, and the surface free energy E1 may be 1,000 times or less, 500 times or less, 100 times or less, or 50 times or less the free energy E2.

[0109] When the balloon 10 is delivered to a treatment site such as a stenotic portion of a blood vessel, it is preferably inserted into a guiding catheter or sheath in a deflated state. At this time, it is preferable that the balloon 10 be appropriately folded so that its radial size is small.

[0110] Figures 28 and 29 show an example of a configuration in which the balloon 10 shown in Figure 5 is deflated and folded. Figures 28 and 29 show cross-sectional views of the deflated balloon 10 cut perpendicular to the longitudinal axis at the discontinuity 24 of the ridges 21. Also shown is an example in which a drug layer 31 is provided from the discontinuity 24 to the ridge-free region 26, as shown in Figure 17.

[0111] As shown in Figures 28 and 29, when the balloon 10 is in a deflated state, the balloon 10 is preferably folded back at the non-ridge regions 26 with the inner surface of the balloon body 16 facing inward, forming folded wing portions 27 where the non-ridge regions 26 overlap, and the folded wing portions 27 are disposed overlapping the outer surface of the balloon 10. The folded wing portions 27 are formed by folding back the non-ridge regions 26 of the balloon body 16 at fold lines 28, with the non-ridge regions 26 overlapping each other. At the fold lines 28, the non-ridge regions 26 are folded back with the inner surface of the balloon body 16 facing inward. Therefore, when viewed from the outside of the balloon 10, the fold lines 28 form a mountain fold. It is preferable that the folded wing portions 27 are formed only from the non-ridge regions 26 of the balloon body 16, and do not include the ridge regions 25.

[0112] The fold lines 28 are preferably formed so as to extend substantially parallel to the extension direction of the ridges 21. The non-ridge region 26 may be folded back so as to form a clear crease at the fold line 28, or may be folded back with a rounded tip. Note that, because the non-ridge region 26 of the balloon body 16 usually has a certain degree of thickness and elasticity, the non-ridge region 26 is folded back with a rounded tip at the fold line 28. In this case, when viewed in a vertical cross section of the balloon 10 in the longitudinal axis direction, the fold line 28 is the tip where the non-ridge region 26 is folded back.

[0113] It is preferable that the bending lines 28 are formed at least in the straight pipe section 13. Therefore, it is preferable that the balloon 10 has folding wing sections 27 formed by overlapping the ridge-free regions 26 in the straight pipe section 13, and that the folding wing sections 27 are arranged overlapping the outer surface of the straight pipe section 13.

[0114] The straight tube section 13 may have a fold line (valley fold line when viewed from the outside of the balloon 10) formed on one and / or the other circumferential side of the fold line 28, where the outer surface of the balloon body 16 faces inward. In this case, the fold line that becomes the valley fold line preferably forms the base of the folding wing section 27.

[0115] Only one fold line 28 may be formed in each non-ridge-streak region 26, or two or more fold lines 28 may be formed in each non-ridge-streak region 26. Preferably, one or two fold lines 28 are formed in each non-ridge-streak region 26. In FIG. 28 , one fold line 28 is formed in each non-ridge-streak region 26, and in FIG. 29 , two fold lines 28 are formed in each non-ridge-streak region 26. When only one fold line 28 is formed in each non-ridge-streak region 26, it is preferable that the folding wings 27 are inclined to one side in the circumferential direction when viewed in a vertical cross section of the balloon 10 taken along the longitudinal axis. When two fold lines 28 are formed in each non-ridge-streak region 26, it is preferable that the two folding wings 27 are inclined in opposite directions in the circumferential direction toward the ridges 21 when viewed in a vertical cross section of the balloon 10 taken along the longitudinal axis. This makes it easier for the ridges 21 to be protected by the folding wings 27 when the balloon 10 is in a deflated state.

[0116] In one embodiment, when balloon 10 is in a deflated state, folding wings 27 may be arranged to cover apex 21A of ridge 21. In this case, drug layer 31 provided on end surface 22 of ridge 21 is protected by folding wings 27, making drug layer 31 less likely to fall off balloon 10 before balloon 10 is delivered to the treatment target area.

[0117] In another embodiment, when the balloon 10 is in a deflated state, the folding wings 27 may be arranged overlapping the outer surface of the straight tube section 13 so as not to cover the apex 21A of the ridges 21. In this case, when the balloon 10 is inflated at a narrowed area, the ridges 21 quickly bite into the narrowed area, making it easier for the balloon 10 to effectively dilate the narrowed area.

[0118] In Figure 28, one folded blade portion 27 is formed in one ridge-free region 26, and the folded blade portion 27 is arranged so as to cover the top 21A of the ridge 21, but in Figure 28, the folded blade portion 27 may be arranged so as to overlap the outer surface of the straight pipe portion 13 so as not to cover the top 21A of the ridge 21. In Figure 29, two folded blade portions 27 are formed in one ridge-free region 26, and the folded blade portion 27 is arranged so as to overlap the outer surface of the straight pipe portion 13 so as not to cover the top 21A of the ridge 21, but the folded blade portion 27 may be arranged so as to cover the top 21A of the ridge 21.

[0119] This application claims the benefit of priority based on Japanese Patent Application Nos. 2024-010302 and 2024-010304 filed on January 26, 2024, Japanese Patent Application No. 2024-077680 filed on May 13, 2024, and Japanese Patent Application No. 2024-232071 filed on December 27, 2024. The entire contents of the specifications of Japanese Patent Application Nos. 2024-010302 and 2024-010304 filed on January 26, 2024, Japanese Patent Application No. 2024-077680 filed on May 13, 2024, and Japanese Patent Application No. 2024-232071 filed on December 27, 2024 are incorporated herein by reference.

[0120] 1: Balloon catheter 2: Shaft 3: Inner shaft 4: Outer shaft, 4A: Proximal outer shaft, 4B: Distal outer shaft 5: Hub 6: Fluid injection section 7: Guidewire port 8: Distal tip 9: Radiopaque marker 10: Balloon 11: Proximal sleeve section 12: Proximal tapered section 13: Straight tube section 14: Distal tapered section 15: Distal sleeve section 16: Balloon body section 17: Proximal section 18: Middle section 19: Distal section 21: Ridge, 21A: Apex, 21B: Base 22: (Ridge) end face, 22P: Proximal end face, 22D: Distal end face, 22A: Apex (of end face), 22B: Base (of end face) 23: (Ridge) side face 24: Discontinued section 25: Ridge presence region 26: Region without ridges 27: Folding wing portion 28: Bending line 29: First stage portion 30: Second stage portion 31: Drug layer 32: Shortest point from the base of the end face of the ridge to the surface of the drug layer 33: Crack 35: Protective layer

Claims

1. A balloon for a balloon catheter having a longitudinal axis direction extending from the proximal side to the distal side, a radial direction perpendicular to the longitudinal axis direction, and a circumferential direction, wherein the balloon has a balloon main body portion and a ridge protruding radially outward on the outer surface of the balloon main body portion, and a drug layer is provided on an end face of the ridge.

2. The balloon according to claim 1, wherein 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, and the drug layer is provided on the end face of the ridge in the straight tube portion.

3. The balloon according to claim 1, wherein the thickness of the drug layer at the base of the end face is greater than the thickness of the drug layer at the top of the end face.

4. The balloon according to claim 1, wherein a plurality of the ridges are provided side by side in the longitudinal axis direction, a break portion is formed between the plurality of ridges, and the drug layer is provided on the end face of the ridge facing the break portion.

5. The balloon according to claim 4, wherein the break portion includes a specific break portion provided with the drug layer satisfying the following requirements. (Requirements) The drug layer is provided from the distal end face of the ridge adjacent to the proximal side of the specific break portion to the proximal end face of the ridge adjacent to the distal side of the specific break portion.

6. The balloon according to claim 4, wherein the break portion includes a specific break portion provided with the drug layer satisfying the following requirements. (Requirements) In a cross section along the longitudinal axis direction and the radial direction passing through the top of the ridge, the thickness of the drug layer at the base of the distal end face of the ridge adjacent to the proximal side of the specific break portion and the thickness of the drug layer at the base of the proximal end face of the ridge adjacent to the distal side of the specific break portion are greater than the thickness of the drug layer at the center of the specific break portion in the longitudinal axis direction.

7. The balloon according to claim 4, wherein the break portion includes a specific break portion provided with the drug layer that satisfies the following requirements. (Requirements) In a cross-section along the longitudinal axis direction and the radial direction passing through the top of the ridge, the distal end surface of the ridge adjacent to the proximal side of the specific break portion has a portion extending radially from the base to the top and / or a portion extending distally of the end surface, and the proximal end surface of the ridge adjacent to the distal side of the specific break portion has a portion extending radially from the base to the top and / or a portion extending proximally of the end surface.

8. The balloon according to claim 7, wherein a part of the distal end surface of the ridge adjacent to the proximal side of the specific break portion is in contact with a part of the proximal end surface of the ridge adjacent to the distal side of the specific break portion.

9. The balloon according to claim 4, wherein the break portion includes a specific break portion provided with the drug layer that satisfies the following requirements. (Requirements) The outer surface of the balloon is divided into a ridge presence region and a ridge absence region in the circumferential direction. In a cross-section perpendicular to the longitudinal axis direction passing through the center of the specific break portion in the longitudinal axis direction, the average thickness of the drug layer in the specific break portion is thicker than the average thickness of the drug layer in the ridge absence region.

10. The balloon according to claim 1, wherein the end surface of the ridge is formed to be recessed.

11. The balloon according to claim 1, wherein cracks extending along the base of the end surface of the ridge are formed on the surface of the drug layer.

12. The balloon according to claim 1, wherein the ridge is formed in multiple stages, and cracks extending along the base of any stage of the end surface of the ridge are formed on the surface of the drug layer.

13. The balloon according to claim 1, wherein the drug constituting the drug layer is crystalline.

14. The balloon according to claim 1, wherein the surface free energy of the constituent material of the surface of the ridge is different from the surface free energy of the constituent material of the outer surface of the balloon main body portion.

15. The balloon according to claim 1, wherein the surface free energy of the constituent material of the surface of the ridge is greater than the surface free energy of the constituent material of the outer surface of the balloon main body portion.

16. The balloon according to claim 1, wherein the ridge is made of resin, metal, or a combination thereof.

17. The outer surface of the balloon is divided in the circumferential direction into a rib present region and a rib absent region. In the contracted state of the balloon, the balloon is folded back in the rib absent region with the inner surface of the balloon body portion facing inward, and a folded fin portion in which the rib absent regions are overlapped is formed. The folded fin portion is disposed so as to overlap the outer surface of the balloon and covers the top of the rib. The balloon according to claim 1.

18. The outer surface of the balloon is divided in the circumferential direction into a rib present region and a rib absent region. In the contracted state of the balloon, the balloon is folded back in the rib absent region with the inner surface of the balloon body portion facing inward, and a folded fin portion in which the rib absent regions are overlapped is formed. The folded fin portion is disposed so as to overlap the outer surface of the balloon so as not to cover the top of the rib. The balloon according to claim 1.

19. A balloon catheter comprising the balloon according to any one of claims 1 to 18.

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