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), notches (22) are formed in the protrusions (21), and a drug layer (41) is provided in the notches (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 and a balloon catheter including the balloon of the present invention that have solved the above-mentioned problems 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 a ridge protruding radially outward from the outer surface of the balloon main body, with notches formed in the ridge, and a drug layer provided in the notch of the ridge. [2] The balloon described in [1], the balloon having 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 in the notch of the ridge in the straight tube section. [3] The balloon described in [1] or [2], wherein the notch includes a specific notch provided with the drug layer that satisfies the following requirements: (Requirement) The outer surface of the balloon is divided into a region with ridges and a region without ridges, and in a cross section perpendicular to the longitudinal axis direction and passing through the bottom of the specific notch, the average thickness of the drug layer in the specific notch is thicker than the average thickness of the drug layer in the region without ridges. [4] The balloon according to any of [1] to [3], wherein the notches include specific notches that satisfy the following requirement: (Requirement) In a cross section passing through the top of the ridge and along the extension direction and radial direction of the ridge, at least a portion of the outer edge on the proximal side of the specific notch is located proximal to an imaginary line connecting the top and bottom of the outer edge on the proximal side of the specific notch, and / or at least a portion of the outer edge on the distal side of the specific notch is located distal to an imaginary line connecting the top and bottom of the outer edge on the distal side of the specific notch. [5] The balloon according to any one of [1] to [4], wherein the notches include specific notches in which the drug layer is provided that satisfy the following requirement: (Requirement) In a cross section passing through the top of the ridge and along the extension direction and radial direction of the ridge, the surface of the drug layer provided in the specific notch is recessed radially inward, and the drug layer is present at the bottom of the specific notch. [6] The balloon according to any one of [1] to [5], wherein the notches include specific notches in which the drug layer is provided that satisfy the following requirement:(Requirement) In a cross section passing through the top of the ridge and taken along the extension direction and radial direction of the ridge, the shortest distance from the outer edge of the specific notch covered with the drug layer to the surface of the drug layer is longest at any point other than the bottom of the specific notch. [7] The balloon according to any of [1] to [6], wherein the notches include specific notches provided with the drug layer that satisfy the following requirement. (Requirement) In a cross section perpendicular to the extension direction of the ridge, the proximal and / or distal surfaces of the specific notches are formed to be recessed radially inward. [8] The balloon according to any of [1] to [7], wherein the ridge is divided into a plurality of ridge segments by the notches, and the notches include specific notches provided with the drug layer that satisfy the following requirement. (Requirement) The distal surface of the ridge segment adjacent to the proximal side of the specific notch (hereinafter referred to as the "proximal ridge segment") has a portion extending radially from the bottom to the top of the specific notch and / or a portion extending toward the distal side in a cross section passing through the apex of the ridge and along the extension direction and radial direction of the ridge, and the proximal surface of the ridge segment adjacent to the distal side of the specific notch (hereinafter referred to as the "distal ridge segment") has a portion extending radially from the bottom to the top of the specific notch and / or a portion extending toward the proximal side in a cross section passing through the apex of the ridge and along the extension direction and radial direction of the ridge. [9] The balloon according to [8], wherein a portion of the distal surface of the proximal ridge segment is in contact with a portion of the proximal surface of the distal ridge segment.

[10] The balloon according to any one of [1] to [9], wherein, in a cross section perpendicular to the extension direction of the ridges, the ridges are formed in a stepped shape with a narrowing width toward the top of the ridges, and have a first step portion adjacent to the outer surface of the balloon body and a second step portion closer to the top, and the notch is formed in the second step portion but not in the first step portion.

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

[10] , wherein a crack extending along the bottom of the notch is formed in the surface of the drug layer.

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

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

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

[12] , 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.

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

[12] , 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.

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

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

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

[15] , wherein the outer surface of the balloon is divided into a ridge-present 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 main body facing inward to form folded wing portions where the ridge-free regions are overlapped, and the folded wing portions are arranged overlapping the outer surface of the balloon and cover the tops of the ridges.

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

[15] , wherein the outer surface of the balloon is divided 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 portions where the ridge-free regions are overlapped, and the folded wing portions are arranged overlapping the outer surface of the balloon so as not to cover the tops of the ridges.

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

[17] .

[0007] The balloon for a balloon catheter of the present invention has ridges on its outer surface, with a drug layer disposed in the notches 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 the balloon, 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 with the drug layer on the balloon surface removed. 1 shows a II-II cross-sectional view of the balloon catheter shown in FIG. 1. 1 shows a III-III cross-sectional view of the balloon catheter shown in FIG. 1. 1 shows a perspective view of a balloon provided in the balloon catheter shown in FIG. 1. 1 shows a vertical cross-sectional view in the longitudinal axis direction of the balloon shown in FIG. 4. 1 shows an enlarged cross-sectional view of the ridges of the balloon shown in FIG. 5. 1 shows an example of a ridge in which a drug layer is provided in its cutouts, and is a cross-sectional view of the ridge along the extension direction of the ridge. 1 shows another example of a ridge in which a drug layer is provided in its cutouts, and is a cross-sectional view of the ridge along the extension direction of the ridge. 1 shows another example of a ridge in which a drug layer is provided in its cutouts, and is a cross-sectional view of the ridge along the extension direction of the ridge. 11 shows a cross-sectional view taken along line XI-XI of the notch in the ridge shown in Figure 7. It shows an example of a ridge in which a drug layer is provided on the side surface of the ridge, and is a vertical cross-sectional view in the longitudinal axis direction of the ridge. It shows another example of a ridge provided on a balloon, and is a perspective view of the notch in the ridge. It shows an example of a ridge in which a drug layer is provided in the notch of the ridge, and cracks are formed in the surface of the drug layer, and is a perspective view of the ridge. It shows a cross-sectional view of the ridge along the extension direction of the ridge, and is an example of a configuration in which a drug layer is provided in the notch of the ridge shown in Figure 14. It shows another example of a ridge in which a drug layer is provided in the notch 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. It shows another example of a ridge in which a drug layer is provided in the notch 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. 15 shows another example of a convex rib in which a drug layer is provided in the notch of the convex rib and cracks are formed on the surface of the drug layer, and is a cross-sectional view of the convex rib along the extension direction of the convex rib. In the cross-sectional view of the convex rib along the extension direction of the convex rib shown in FIG. 15, a configuration example is shown in which a protective layer is provided on the outer surface of the drug layer provided in the notch of the convex rib. Another example of a convex rib in which a drug layer is provided in the notch of the convex rib, is a cross-sectional view of the convex rib along the extension direction of the convex rib. Another example of a convex rib in which a drug layer is provided in the notch of the convex rib, is a cross-sectional view of the convex rib along the extension direction of the convex rib.24 and 25.

[0033] FIG. 25 shows another example of a ridge in which a drug layer is provided in the notch of the ridge, and is a cross-sectional view of the ridge along the extension direction of the ridge.

[0034] FIG. 26 shows another example of a ridge provided on a balloon, and is a perspective view of the ridge.

[0035] FIG. 27 shows another example of a ridge in which a drug layer is provided in the notch of the ridge, and is a cross-sectional view of the ridge along the extension direction of the ridge.

[0036] FIG. 28 shows another example of a ridge in which a drug layer is provided in the notch of the ridge, and is a cross-sectional view of the ridge along the extension direction of the ridge.

[0037] FIG. 29 shows another example of a ridge in which a drug layer is provided in the notch 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.

[0038] FIG. 29 shows an example of a folded state of the balloon shown in FIG. 4, and is a vertical cross-sectional view of the folded balloon in the longitudinal axis direction. 5 shows another example of the folded state of the balloon shown in FIG. 4, and is a vertical cross-sectional view of the folded balloon in 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 the configuration of a balloon catheter equipped with the balloon will be described with reference to the drawings. Figures 1 to 6 show an example of the configuration of a balloon catheter without the drug layer of the balloon. 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 on the balloon catheter shown in Figure 1, Figure 5 shows a vertical cross-sectional view of the balloon shown in Figure 4 taken along the longitudinal axis, and Figure 6 shows an enlarged cross-sectional view of the ridges of the balloon shown in Figure 5. Figure 1 shows an example of the configuration 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 Figure 4, 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 the 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 the 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 5 and 6. Figure 5 shows a vertical cross-section of the straight pipe portion 13 of the balloon 10 in the longitudinal direction, and Figure 6 shows an enlarged cross-section of the ribs 21 of the balloon 10. Figure 5 shows an example of the configuration of a vertical cross-section of the straight pipe portion 13 of the balloon 10 shown in Figure 4 in the longitudinal direction at a location where the ribs 21 are provided, with the ribs 21 provided at three locations around the circumferential direction of the straight pipe portion 13.

[0032] The balloon 10 has a balloon body 16, and a ridge 21 is provided on the outer surface of the balloon body 16. The ridge 21 is provided so as to protrude radially outward from the outer surface of the balloon body 16. By providing the ridge 21 in the balloon 10, a ridge-present region 27 and a ridge-free region 28 are formed on the outer surface of the straight pipe section 13. Note that the ridge-present region 27 also includes a portion of the ridge 21 where a notch 22 is formed, as described below.

[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 27 is composed of the balloon body 16 and the ridges 21, and the ridge-free region 28 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 28. 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 28. 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 28 means that the streak-free region 28 has an arched shape in a flat plane, and no irregularities are formed in the arched 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 28 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] 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 28 is formed on the balloon 10, and when multiple ridges 21 are provided on the balloon 10, multiple non-ridge regions 28 are formed on the balloon 10. The same number of non-ridge regions 28 as the number of ridges 21 are formed.

[0041] 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.

[0042] The plurality of ridges 21 are preferably provided at approximately the same position in the longitudinal axis direction. That is, the proximal ends of the plurality of ridges 21 are preferably located at approximately the same position in the longitudinal axis direction, and the distal ends of the plurality of ridges 21 are preferably located at approximately the same position in the longitudinal axis direction.

[0043] 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.

[0044] 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.

[0045] In the balloon 10, the thickness of the portion where the ridges 21 are provided, i.e., the ridge-presence region 27, is preferably thicker than the thickness of the portion where the ridges 21 are not provided, i.e., the ridge-free region 28. This enhances the scoring function of the ridges 21. The thickness (maximum thickness) of the ridge-presence region 27 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 28. There is no particular upper limit to the thickness of the ridge-presence region 27, 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 28.

[0046] 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.

[0047] A balloon 10 provided with ridges 21 tends to exhibit increased rigidity in the areas where the ridges 21 are provided. Therefore, compared to a balloon 10 without ridges 21, the balloon 10 with ridges 21 is more likely to have reduced flexibility in the longitudinal direction. 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 has ridges. Alternatively, a balloon for lower limbs may be inserted through the iliac artery during treatment, where the blood vessels bend significantly at the bifurcation point where the left and right iliac arteries branch from the abdominal aorta. Therefore, if a balloon for lower limbs has ridges, it may be difficult to pass the balloon from one iliac artery to the other. In particular, due to the long length of a balloon for lower limbs, there is a high risk that the balloon will be unable to pass through a portion of the blood vessel where the blood vessel bends significantly. Therefore, as shown in FIG. 4 , the balloon 10 has notches 22 formed in the ridges 21. By forming the notches 22 in the ridges 21, the flexibility of the balloon 10 in the longitudinal axis direction can be improved.

[0048] The notch 22 may be formed by removing a portion of the apex 21A of the ridge 21. While Figures 7 to 10 show cross-sectional views of the ridge 21, passing through the apex 21A of the ridge 21 and along the extension and radial directions of the ridge 21, the notch 22 may extend from the apex 21A to the base 21B of the ridge 21, as shown in Figures 7 and 9, or may extend partway from the apex 21A to the base 21B of the ridge 21, as shown in Figures 8 and 10. In the former case, the depth of the notch 22 is equal to the height of the ridge 21. In the latter case, the depth of the notch 22 is shorter than the height of the ridge 21. Figures 7 to 10 show cross-sectional views of the ridge 21, including the notch 22, taken along an imaginary plane passing through the apex 21A of the ridge 21 and formed by the extension direction of the ridge 21 and the radial direction of the balloon 10. The notch 22 may be formed by cutting a part of the ridge 21 or by molding the ridge 21 into a shape having the notch 22, and the method of forming the notch 22 is not particularly limited.

[0049] The notch 22 has a bottom 22B and a top 22A. In the notch 22, the bottom 22B refers to the radially innermost portion of the notch 22, and the top 22A refers to the radially outermost portion of the notch 22. The top 22A of the notch 22 coincides with the top 21A of the ridge 21. The radial length from the top 22A to the bottom 22B of the notch 22 is the depth of the notch 22. In Figures 7 to 10, the bottom 22B of the notch 22 is formed so that its length in the extension direction of the ridge 21 is zero, but the bottom 22B of the notch 22 may be formed to have a predetermined length in the extension direction of the ridge 21. In this case, the bottom 22B of the notch 22 is formed to extend parallel to the extension direction of the ridge 21, and the bottom 22B has a predetermined length in the extension direction of the ridge 21. For example, the bottom 22B of the notch 22 may be formed to a predetermined length in the extension direction of the ridge 21, and the notch 22 may be formed to extend partway to the base 21B of the ridge 21.

[0050] The depth of the notches 22 is preferably at least 0.3 times, more preferably at least 0.5 times, and even more preferably at least 0.7 times the height of the ridges 21. This facilitates increasing the flexibility of the balloon 10 in the longitudinal direction and, as will be described later, makes it easier to retain a larger amount of drug in the notches 22. There is no particular upper limit to the depth of the notches 22, and the depth of the notches 22 may be no more than 1.0 times the height of the ridges, or may be less than 1.0 times.

[0051] In a cross section passing through the apex 21A of the ridge 21 along the extending direction and radial direction of the ridge 21, the shape of the outer edge of the notch 22 is not particularly limited. The outer edge of the notch 22 may be formed linearly as shown in Figures 7 and 8, or may be formed curvedly as shown in Figures 9 and 10. The proximal outer edge 23P of the notch 22 may extend proximally from the bottom 22B toward the apex 22A, may extend distally, or may extend radially. The distal outer edge 23D of the notch 22 may extend distally from the bottom 22B toward the apex 22A, may extend proximally, or may extend radially. In Figures 7 to 10, the proximal outer edge 23P of the notch 22 extends proximally from the bottom 22B toward the top 22A, and the distal outer edge 23D of the notch 22 extends distally from the bottom 22B toward the top 22A.

[0052] It is preferable that the notches 22 are formed in each of the ridges 21. This allows the flexibility of the balloon 10 to be improved regardless of the direction in which the balloon 10 bends.

[0053] The ridge 21 is divided into a plurality of ridge segments 24 by the notches 22. Specifically, the ridge 21 is divided into a proximal ridge segment 24 and a distal ridge segment 24, with the bottom 22B of the notch 22 as the boundary. Hereinafter, the ridge segment 24 adjacent to the proximal side of the notch 22 will be referred to as the proximal ridge segment 24P, and the ridge segment 24 adjacent to the distal side of the notch 22 will be referred to as the distal ridge segment 24D. When the bottom 22B of the notch 22 is formed with a predetermined length in the extension direction of the ridge 21, the proximal ridge segment 24P is formed proximally of the proximal end of the bottom 22B of the notch 22, and the distal ridge segment 24D is formed distally of the distal end of the bottom 22B of the notch 22. That is, the proximal end of the bottom 22B of the notch 22 is the distal boundary of the proximal ridge segment 24P, and the distal end of the bottom 22B of the notch 22 is the proximal boundary of the distal ridge segment 24D.

[0054] In each ridge 21, the length between the apexes 22A of the notches 22 (if multiple notches 22 are provided, the length between the apexes 22A of each notch 22) is preferably shorter than the length in the extension direction of the ridge segment 24. In each ridge 21, the length between the apexes 22A of the notches 22 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 length in the extension direction of the ridge segments 24. This makes it easier to ensure the scoring function of the ridge 21. Note that the extension length of the ridge segment 24 described here means the length of the apex 21A of the ridge segment 24.

[0055] In each ridge 21, the total length between the apexes 22A of the notches 22 is preferably 20% or less, more preferably 15% or less, and even more preferably 10% or less of the length of the ridge 21 in the extension direction. This makes it easier to ensure the scoring function of the ridge 21. The length of the ridge 21 in the extension direction is the length including the notches 22A and the ridge segments 24.

[0056] In each notch 22, the length between the apexes 22A of the notches 22 is preferably at least 0.2 times the depth of the notch 22, more preferably at least 0.3 times, and even more preferably at least 0.5 times. This facilitates increasing the longitudinal flexibility of the straight tube portion 13 of the balloon 10 and, as described below, facilitates holding a larger amount of drug in the notches 22. In each notch 22, the length between the apexes 22A of the notches 22 is preferably no more than 5 times the depth of the notch 22, more preferably no more than 3 times, and even more preferably no more than 2 times. This facilitates ensuring the scoring function of the balloon 10.

[0057] The distal surface 25 of the proximal ridge segment 24P and the proximal surface 26 of the distal ridge segment 24D may be flat, curved, or a combination thereof. The shape of the distal surface 25 of the proximal ridge segment 24P may be the same as or different from the shape of the proximal surface 26 of the distal ridge segment 24D. Furthermore, the shapes of the distal surfaces 25 of multiple proximal ridge segments 24P may be the same as or different from each other, and the shapes of the proximal surfaces 26 of multiple distal ridge segments 24D may be the same as or different from each other. The distal surface 25 of the proximal ridge segment 24P refers to the portion of the proximal ridge segment 24P facing the distal side, and includes the proximal outer edge 23P of the notch 22. The proximal surface 26 of the distal ridge segment 24D means the portion of the distal ridge segment 24D facing the proximal side, and includes the distal outer edge 23D of the notch 22.

[0058] The notches 22 of the ridges 21 are preferably formed at least in the straight tube portion 13 of the balloon 10. This improves the longitudinal flexibility of the balloon 10. When the straight tube portion 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 notches 22 of the ridges 21 may be provided in any of the proximal section 17, the intermediate section 18, and the distal section 19.

[0059] In one embodiment, the notches 22 are preferably provided in the distal section 19 of the straight tube section 13. By forming the notches 22 in 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, it is preferable that the notches 22 be provided in the distal section 19 of each ridge 21 provided in the straight tube section 13.

[0060] It is also preferable that the notch 22 be provided in the proximal section 17 of the straight tube section 13. This increases the flexibility of the proximal portion of the balloon 10 (specifically, the proximal section 17 of the straight tube section 13), and improves the insertability of the balloon 10 through the curved section when the balloon 10 is pulled back and passed through a curved section of a blood vessel or the like after treatment with the balloon 10. In this case, it is preferable that the notch 22 be provided in the proximal section 17 of each ridge 21 provided on the straight tube section 13.

[0061] The notch 22 does not have to be provided in the intermediate section 18 of the straight tube section 13. Forming the ridge 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 notch 22 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 notch 22 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 the notch 22 to hold a larger amount of drug, as described below.

[0062] The number of notches 22 formed in each ridge 21 is not particularly limited as long as it is one or more, but from the viewpoint of improving the flexibility of the balloon 10, the number of notches 22 formed in each ridge 21 is preferably two or more, and more preferably three or more. On the other hand, from the viewpoint of ensuring the scoring function of the balloon 10, the number of notches 22 formed in each ridge 21 is preferably 20 or less, more preferably 16 or less, even more preferably 12 or less, and even more preferably 8 or less.

[0063] As shown in Figures 7 to 10, the balloon 10 has a drug layer 41 provided in the notches 22 of the ribs 21. By providing the drug layer 41 in this manner, 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.

[0064] The drug layer 41 provided in the notches 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 28 of the balloon 10 are folded before inflation, and the folds of the non-ridge regions 28 unfold during inflation. However, the drug layer 41 provided in the notches 22 of the ridges 21 is less susceptible to the unfolding movement of the folds of the non-ridge regions 28 during inflation of the balloon 10. Therefore, compared with when the drug layer 41 is provided in the non-ridge regions 28 or on the side surfaces 21S of the ridges 21, the drug layer 41 provided in the notches 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.

[0065] When multiple notches 22 are provided in the convex rib 21, it is sufficient that a drug layer 41 is provided in at least one of the multiple notches 22, and it is preferable that a drug layer 41 is provided in at least 1 / 2 of the notches 22, more preferable that a drug layer 41 is provided in at least 3 / 4 of the notches 22, and even more preferable that a drug layer 41 is provided in all of the notches 22.

[0066] The drug contained in drug layer 41 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 vascular restenosis after angioplasty treatment, anti-restenosis drugs such as antiproliferative agents and immunosuppressants are preferably used as the drug. Specifically, drugs such as paclitaxel, sirolimus (rapamycin), everolimus, and zotarolimus can be used. These drugs may be used alone or in combination of two or more types.

[0067] In addition to the pharmacologically active substance, the drug layer 41 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.

[0068] A protective layer may be provided on the outer surface of the drug layer 41 to prevent the drug from leaching or falling off into bodily 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 bodily fluid containing a large amount of lipid-soluble components, such as a bile duct, a protective layer composed of a hydrophilic component provided on the outer surface of the drug layer 41 can prevent dissolution of the protective layer upon contact with bodily fluids, thereby enabling the protective layer to protect the drug layer 41. 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 41, 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 41. 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.

[0069] 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 41.

[0070] The drug constituting the drug layer 41 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 41, making the drug layer 41 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.

[0071] The drug layer 41 is preferably provided in the notches 22 of the ridges 21 in the straight tube portion 13 of the balloon 10. In this case, it is preferable that at least a portion of the ridges 21 be located in the straight tube portion 13, and that the notches 22 of the ridges 21 be 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, if the drug layer 41 is provided in the notches 22 of the ridges 21 in the straight tube portion 13 of the balloon 10, the drug layer 41 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 ridges 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.

[0072] In notch 22 of ridge 21, drug layer 41 is preferably provided at least on bottom 22B of notch 22. Drug layer 41 may be provided so as to fill the entire notch 22, or may be provided so as to fill only a portion of notch 22. For example, the thickness of drug layer 41 at bottom 22B of notch 22 may be 0.1 times or more, 0.2 times or more, 0.3 times or more, or 0.5 times or more the depth of notch 22.

[0073] In the notch 22, the drug layer 41 is preferably provided from the distal surface 25 of the proximal ridge segment 24P to the proximal surface 26 of the distal ridge segment 24D. If the drug layer 41 is provided in this manner, a larger amount of drug can be held in the notch 22, and the drug layer 41 can be stably held in the notch 22. Therefore, a larger amount of drug can be delivered to the surface of the blood vessel wall.

[0074] The thickness of drug layer 41 at bottom 22B of notch 22 is preferably greater than the thickness of drug layer 41 at top 22A of notch 22. With drug layer 41 formed in this manner, when balloon 10 is inflated at a narrowed portion of the blood vessel, the amount of drug suddenly delivered to the inside of the blood vessel wall is reduced, making it easier to distribute more drug on the surface of the blood vessel wall. This prevents the drug from being partially overdosed inside the blood vessel wall.

[0075] The thickness of drug layer 41 at bottom 22B of notch 22 and the thickness of drug layer 41 at top 22A of notch 22 can be determined by measuring the thickness of drug layer 41 formed in notch 22 in a cross section passing through top 21A of ridge 21 along the extension direction and radial direction of ridge 21. The thickness of drug layer 41 at bottom 22B of notch 22 refers to the shortest distance from bottom 22B of notch 22 to the surface of drug layer 41, i.e., the length from bottom 22B of notch 22 to shortest point 42 on the surface of drug layer 41, and corresponds to the length indicated by arrow L1 in Figures 7 to 10. It is anticipated that cracks may occur on the surface of drug layer 41 due to its dry state. In such a case, the shortest distance to the surface of drug layer 41 excluding the location of the crack is defined as the thickness of drug layer 41 at bottom 22B of notch 22 of ridge 21. The thickness of drug layer 41 at top 22A of notch 22 is zero if drug layer 41 is not present at top 22A, and if drug layer 41 is present at top 22A, it means the shortest thickness of drug layer 41 at top 22A, that is, the shortest distance from top 22A to the surface of drug layer 41. If bottom 22B of notch 22 is formed to a predetermined length in the extension direction of convex rib 21, the thickness of drug layer 41 at bottom 22B of notch 22 is the thickness of drug layer 41 at the point where the shortest distance from bottom 22B to the surface of drug layer 41 is shortest for bottom 22B of the predetermined length.

[0076] It is preferable that the drug layer 41 be formed thicker in the notches 22; for example, it is preferable that the drug layer 41 be formed thicker than in the non-ridge-streak regions 28 on the outer surface of the balloon 10. Figure 11 shows a cross-sectional view taken along line XI-XI at the notches 22 of the ridges 21 shown in Figure 7 (however, only the cross-sectional portion of the drug layer 41 is shown). As shown in Figure 11, it is preferable that the drug layer 41 be formed thicker in the notches 22 than in the non-ridge-streak regions 28, and it is preferable that the drug layer 41 be formed in this manner in at least one notch 22. For example, it is preferable that the notches 22 include a specific notch 22 provided with a drug layer 41 that satisfies the following requirement A. (Requirement A) The outer surface of the balloon 10 is divided into ridge-streak regions 27 and non-ridge-streak regions 28, and in a cross-section perpendicular to the longitudinal axis direction and passing through the bottoms 22B of the specific notches 22, the average thickness of the drug layer 41 in the specific notches 22 is thicker than the average thickness of the drug layer 41 in the non-ridge-streak regions 28.

[0077] The specific notches 22 provided with the drug layer 41 that satisfies the above requirement A 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 portion of the vascular wall surface that is torn by the ridges 21 when the balloon 10 is inflated. As a result, a larger amount of drug can be delivered to the interior of the vascular wall in a sustained manner. The average thickness of the drug layer 41 in the specific notches 22 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 41 in the ridge-free regions 28. The upper limit of the ratio of the average thickness of the drug layer 41 in the specific notches 22 to the average thickness of the drug layer 41 in the ridge-free regions 28 is not particularly limited, and the average thickness of the drug layer 41 in the ridge-free regions 28 may be zero. In addition, since it is preferable that the drug layer 41 is also provided in the non-protruding region 28, the average thickness of the drug layer 41 in a specific notch 22 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 41 in the non-protruding region 28.

[0078] The average thickness of the drug layer 41 at the specific notch 22 and the average thickness of the drug layer 41 at the non-ridge region 28, as required by requirement A, can be determined, for example, as follows: The balloon 10 is cut perpendicular to the longitudinal axis at a position passing through the bottom 22B of the specific notch 22. While the balloon body is maintained in a substantially circular shape, the area of ​​the drug layer 41 at the specific notch 22, the circumferential length of the specific notch 22, and the area of ​​the drug layer 41 at the non-ridge region 28 and the circumferential length of the non-ridge region 28 are measured. The average thickness of each drug layer 41 can be determined from the measured areas and circumferential lengths. The circumferential length of the specific notch 22 refers to the circumferential length at the bottom 22B of the specific notch 22. The area of ​​each drug layer 41 can be easily determined by cutting the balloon 10 perpendicular to the longitudinal axis, photographing the cross section, and processing the image.

[0079] The drug layer 41 does not have to be provided in the non-ridge region 28 on the outer surface of the balloon 10. However, it is preferable to provide the drug layer 41 also in the non-ridge region 28, as this allows the balloon 10 to deliver a larger amount of drug to the narrowed portion of the blood vessel.

[0080] The drug layer 41 may also be provided on the side surface 21S of the ridge 21. Figure 12 shows an example of the configuration of the ridge 21 in which the drug layer 41 is provided on the side surface 21S of the ridge 21, showing a vertical cross section of the ridge 21 in the longitudinal direction. The side surface 21S of the ridge 21 refers to the side surface in the width direction of the ridge 21. In this case, on the side surface 21S of the ridge 21, the thickness of the drug layer 41 at the base 21B of the ridge 21 is preferably thicker than the thickness of the drug layer 41 at the apex 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 narrowed portion of a blood vessel. Furthermore, the ridge 21 is more likely to bite into the narrowed portion, allowing the balloon 10 to effectively dilate the narrowed portion. The drug layer 41 does not necessarily have to be provided on the side surface 21S of the ridge 21. On the side surface 21S of the convex rib 21, the drug layer 41 is not provided, or the drug layer 41 is provided so that the thickness of the drug layer 41 at the base 21B of the convex rib 21 is thicker than the thickness of the drug layer 41 at the top 21A of the convex rib 21, preferably in a range of 60% or more of the extension direction of the convex rib 21, more preferably in a range of 70% or more, even more preferably in a range of 80% or more, and even more preferably in a range of 90% or more.

[0081] The thickness of drug layer 41 at base 21B and apex 21A of side surface 21S of ridge 21 can be determined by measuring the thickness of drug layer 41 formed on side surface 21S of ridge 21 in a vertical cross section in the longitudinal axis direction of balloon 10. The thickness of drug layer 41 at base 21B of side surface 21S of ridge 21 means the shortest distance from base 21B to the surface of drug layer 41 on side surface 21S of ridge 21. If cracks occur in drug layer 41, the shortest distance to the surface of drug layer 41 excluding the location where the cracks occurred is defined as the thickness of drug layer 41 at base 21B of side surface 21S of ridge 21. The thickness of the drug layer 41 at the top 21A of the side 21S of the convex rib 21 is 0 if the drug layer 41 is not present at the top 21A, and if the drug layer 41 is present at the top 21A, it means the shortest thickness of the drug layer 41 at the top 21A, i.e., the shortest distance from the top 21A to the surface of the drug layer 41.

[0082] 9 and 10 , the proximal outer edge 23P and / or the distal outer edge 23D of the notch 22 are preferably formed in a recessed shape in a cross section passing through the apex 21A of the ridge 21 along the extension direction and radial direction of the ridge 21, and it is preferable that at least one notch 22 is formed in this way. Therefore, it is preferable that the notch 22 include a specific notch 22 that satisfies the following requirement B. (Requirement B) In 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, at least a portion of the proximal outer edge 23P of a specific notch 22 is located proximal to an imaginary line connecting the top 22A and bottom 22B of the proximal outer edge 23P of the specific notch 22, and / or at least a portion of the distal outer edge 23D of the specific notch 22 is located distal to an imaginary line connecting the top 22A and bottom 22B of the distal outer edge 23D of the specific notch 22.

[0083] If the notches 22 are formed so as to satisfy the above requirement B, a greater amount of drug can be stably held in the notches 22. More preferably, the entire proximal outer edge 23P of the specific notch 22 is located proximal to the imaginary line connecting the apex 22A and the bottom 22B of the outer edge 23P, and the entire distal outer edge 23D of the specific notch 22 is located distal to the imaginary line connecting the apex 22A and the bottom 22B of the outer edge 23D. For example, the specific notch 22 is preferably formed so as to have a U-shaped outer edge shape in a cross section passing through the apex 21A of the ridge 21 and taken along the extension direction and radial direction of the ridge 21.

[0084] 7 to 10 , in notches 22, the surface of drug layer 41 may be recessed radially inward in a cross section passing through apex 21A of ridge 21 along the extension direction and radial direction of ridge 21. In this case, drug layer 41 may be formed in this manner in at least one notch 22. For example, notches 22 may include specific notches 22 provided with drug layer 41 that satisfies the following requirement C. (Requirement C) In a cross section passing through apex 21A of ridge 21 along the extension direction and radial direction of ridge 21, the surface of drug layer 41 provided in specific notch 22 is recessed radially inward, and drug layer 41 is present at bottom 22B of specific notch 22.

[0085] If drug layer 41 is provided so as to satisfy requirement C above, drug layer 41 can be stably held in specific notch 22. Therefore, drug layer 41 is less likely to fall off from specific notch 22. When drug layer 41 is provided so as to satisfy requirement C above, the thickness of drug layer 41 at bottom 22B of specific notch 22 is not particularly limited, and may be, for example, 0.5 times or less, 0.3 times or less, or 0.2 times or less the depth of specific notch 22.

[0086] The notches 22 may include specific notches 22 provided with drug layer 41 that satisfies the following requirement D: (Requirement D) In ​​a cross section passing through the top 21A of the ridge 21 and along the extension direction and radial direction of the ridge 21, the shortest distance from the outer edge covered by drug layer 41 of the specific notch 22 to the surface of drug layer 41 is longest other than at the bottom 22B of the specific notch 22.

[0087] 10 shows an example of a configuration in which drug layer 41 is provided so as to satisfy requirement D. If drug layer 41 is formed in this manner, drug layer 41 can be stably held in specific notches 22, and drug layer 41 is less likely to fall off from specific notches 22 even when balloon 10 is bent in the longitudinal axis direction. In this case, drug layer 41 is preferably present at bottom 22B of specific notch 22 in a cross section passing through top 21A of ridge 21 along the extension direction and radial direction of ridge 21, and the thickness of drug layer 41 at bottom 22B of specific notch 22 is preferably smaller than the thicknesses of drug layer 41 on the proximal and distal sides thereof. For example, the thickness of the thickest portion of drug layer 41 in specific notch 22 is 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 than the thickness of drug layer 41 in bottom portion 22B of specific notch 22. This allows drug layer 41 to be formed with an appropriate thickness over a wide area of ​​specific notch 22.

[0088] The notches 22 may include specific notches 22 that satisfy the following requirement E: (Requirement E) The proximal surface and / or distal surface of the specific notch 22 is formed to be recessed radially inward in a vertical cross section in the extension direction of the ridge 21.

[0089] FIG. 13 shows an example of a perspective view of a ridge 21 in which the proximal and distal surfaces of the notches 22 are formed to satisfy requirement E. Note that the drug layer 41 is omitted from FIG. 13 . If the notches 22 are formed to satisfy requirement E, a greater amount of drug can be stably retained in the notches 22. The proximal surface of a particular notch 22 corresponds to the distal surface 25 of the proximal ridge segment 24P, and the distal surface of a particular notch 22 corresponds to the proximal surface 26 of the distal ridge segment 24D. In FIG. 13 , in a cross section along the extension direction and circumferential direction of the ridge 21, the proximal and distal surfaces of the notch 22 can be seen as recessed. Specifically, at least a portion of the proximal surface of the notch 22 is recessed proximally, and at least a portion of the distal surface of the notch 22 is recessed distally. The particular notch 22 may be formed in a shape that satisfies both requirements B and E.

[0090] As shown in Figures 14 to 18, it is preferable that a crack 43 extending along the bottom 22B of the notch 22 of the ridge 21 is formed on the surface of the drug layer 41. Figures 14 to 18 show configuration examples of the ridge 21 in which a crack 43 is formed in the drug layer 41 provided in the notch 22. Figure 14 shows a perspective view of the ridge 21 in which a crack 43 is formed in the drug layer 41 in the notch 22, and Figures 15 to 18 show configuration examples in which a crack 43 is formed in the drug layer 41 in the notch 22 shown in Figures 7 to 10. Figures 15 to 18 show cross-sectional views of the ridge 21 passing through the top 21A of the ridge 21, along the extension direction of the ridge 21 and the radial direction of the balloon 10. By forming cracks 43 on the surface of the drug layer 41 provided in the notches 22 of the ridges 21, when the drug layer 41 comes into contact with the inner surface of the blood vessel wall when the balloon 10 is expanded at the narrowed area, the drug layer 41 provided in the notches 22 of the ridges 21 becomes more likely to peel off from the surface of the balloon 10 starting from the cracks 43, making it easier for the drug layer 41 to migrate from the surface of the balloon 10 toward the blood vessel wall.

[0091] When viewed from the outside of the balloon 10, the cracks 43 are preferably formed on the surface of the drug layer 41 so as to extend along the bottoms 22B of the notches 22, i.e., along the extension direction of the bottoms 22B (see FIG. 14 ). The cracks 43 may be formed so as to extend parallel to the extension direction of the bottoms 22B, or at least a portion of the cracks 43 may be formed so as to extend obliquely relative to the extension direction of the bottoms 22B. It is sufficient that the cracks 43 as a whole extend along the extension direction of the bottoms 22B of the notches 22. The cracks 43 may be formed so as to extend continuously along the bottoms 22B, or so as to extend intermittently. Furthermore, at least a portion of the multiple cracks 43 extending along the bottoms 22B may be aligned in the extension direction of the ridges 21.

[0092] 15 to 18 , in a cross section taken along the extension direction and radial direction of ridge 21, crack 43 is preferably formed at or near point 42 on the surface of drug layer 41 that is closest to bottom 22B of notch 22. Specifically, in a vertical cross section taken along the extension direction and radial direction of ridge 21, a straight line is drawn connecting bottom 22B of notch 22 in ridge 21 to shortest point 42 on the surface of drug layer 41, and the length of the line from bottom 22B to shortest point 42 is defined as R. In a cross section taken along the extension direction and radial direction of ridge 21, crack 43 on the surface of drug layer 41 is preferably located inside imaginary circle 44 that is centered at bottom 22B and has a radius of 1.5R. More preferably, in a cross section taken along the extension direction and radial direction of ridge 21, crack 43 is preferably entirely contained inside imaginary circle 44 that is centered at bottom 22B and has a radius of 1.5R. 15 to 18, a part of an imaginary circle 44 having a radius of 1.5R and centered on the bottom portion 22B is shown by a dashed line. The radius of the imaginary circle 44 is more preferably 1.3R.

[0093] In a cross section along the extension direction and radial direction of the convex rib 21, the crack 43 may be formed so as to extend from the surface of the drug layer 41 to the outer surface of the balloon 10, or may be formed so as to extend from the surface of the drug layer 41 to the interior of the drug layer 41 as its end point.

[0094] When a plurality of notches 22 are present in ridge 21, it is sufficient that crack 43 is formed in drug layer 41 along at least one bottom 22B of the plurality of bottoms 22B of notches 22. When a plurality of ridges 21 are provided, it is sufficient that crack 43 is formed in drug layer 41 along at least one bottom 22B of notch 22 of each ridge 21.

[0095] Cracks 43 in drug layer 41 can be formed, for example, by bending balloon 10 in the longitudinal direction after drug layer 41 is formed in notch 22 of ridge 21. In this case, balloon 10 is preferably bent in the longitudinal direction at or near the location of notch 22 in ridge 21 in the longitudinal direction.

[0096] When crack 43 is formed on the surface of drug layer 41 provided in notch 22, the thickness of drug layer 41 at bottom 22B of notch 22 means the thickness of drug layer 41 excluding the location where crack 43 is formed. In other words, when a straight line is drawn connecting bottom 22B of notch 22 to shortest point 42 on the surface of drug layer 41, the thickness is the length of the line from bottom 22B to shortest point 42, and shortest point 42 is measured from bottom 22B to the shortest point on the surface of drug layer 41 excluding the location where crack 43 is formed.

[0097] As shown in Figure 19, a protective layer 45 may be provided on the outer surface of the drug layer 41, and the protective layer 45 may be provided to cover at least a portion of the crack 43. Figure 19 shows an example of a configuration in which the protective layer 45 is provided on the outer surface of the drug layer 41 so as to cover the crack 43 in the cross-sectional view of the ridge 21 shown in Figure 15. By providing the protective layer 45 on the outer surface of the drug layer 41 so as to cover at least a portion of the crack 43, it is possible to prevent bodily fluids from entering the crack 43 during delivery of the balloon 10 to the stenotic area, which could cause the drug layer 41 to fall off or the drug to elute from the drug layer 41. The protective layer 45 is preferably provided on the outer surface of the drug layer 41 so as to cover the entire crack 43. It is also preferable that the protective layer 45 be provided so as to penetrate into the crack 43 and fill at least a portion of the crack 43.

[0098] 12 , when drug layer 41 is also provided on side surface 21S of ridge 21, cracks may be formed in drug layer 41 provided on side surface 21S of ridge 21 along base 21B of side surface 21S of ridge 21 (not shown). In this case, it is preferable that the cracks be formed on the surface of drug layer 41 so as to extend along the extending direction of base 21B, i.e., along the extending direction of the boundary between ridge-present region 27 and ridge-free region 28, when balloon 10 is viewed from the outside.

[0099] When cracks 43 are formed on the surface of drug layer 41 provided in notch 22, drug layer 41 only needs to satisfy requirement A described above except for the portion where cracks 43 are formed, and it can be considered that the drug is present even in cracks 43. The same applies to requirement C, requirement E, and various other configurations of drug layer 41.

[0100] In the ridge 21 described above, the proximal outer edge 23P of the notch 22, i.e., the distal surface 25 of the proximal segment 24P, is formed to extend proximally from the bottom 22B of the notch 22 toward the apex 22A, and the distal outer edge 23D of the notch 22, i.e., the distal surface 26 of the distal segment 24D, is formed to extend distally from the bottom 22B of the notch 22 toward the apex 22A, but the notch 22 may include a specific notch 22 provided with a drug layer 41 that satisfies the following requirement F, as shown in Figures 20 to 22. Figures 20 to 22 show examples of the configuration of a specific interrupted portion 24, and show cross-sectional views passing through the apex 21A of the ridge 21 along the extension direction and radial direction of the ridge 21. (Requirement F) In a specific notch 22, the distal surface 25 of the proximal ridge segment 24P has, in a cross section passing through the top 21A of the ridge 21 and along the extension direction and radial direction of the ridge 21, a portion extending radially from the bottom 22B of the specific notch 22 toward the top 22A and / or a portion extending toward the distal side, and the proximal surface 26 of the distal ridge segment 24D has, in a cross section passing through the top 21A of the ridge 21 and along the extension direction and radial direction of the ridge 21, a portion extending radially from the bottom 22B of the specific notch 22 toward the top 22A and / or a portion extending toward the proximal side.

[0101] In Figure 20, the distal surface 25 of the proximal ridge segment 24P has a portion that extends distally from the bottom 22B toward the apex 22A of the particular notch 22, and the proximal surface 26 of the distal ridge segment 24D has a portion that extends proximally from the bottom 22B toward the apex 22A of the particular notch 22. In Figure 21, the distal surface 25 of the proximal ridge segment 24P has a portion that extends radially from the bottom 22B toward the apex 22A of the particular notch 22, and the proximal surface 26 of the distal ridge segment 24D has a portion that extends radially from the bottom 22B toward the apex 22A of the particular notch 22. 22, the distal surface 25 of the proximal ridge segment 24P has a portion that extends radially from the bottom 22B of the specific notch 22 toward the apex 22A and a portion that extends distally, and the proximal surface 26 of the distal ridge segment 24D has a portion that extends radially from the bottom 22B of the specific notch 22 toward the apex 22A and a portion that extends proximally. If the specific notch 22 is formed in this manner, a larger portion of the apex 21A of the ridge 21 will come into contact with the blood vessel wall when the balloon 10 is inflated, thereby allowing the ridge 21 to exert its scoring function more effectively.

[0102] 21 and 22 , in a particular notch 22, the distal surface 25 of the proximal ridge segment 24P may have a portion extending proximally from the bottom 22B toward the apex 22A, and the proximal surface 26 of the distal ridge segment 24D may have a portion extending distally from the bottom 22B toward the apex 22A. Preferably, the portion of the distal surface 25 of the proximal ridge segment 24P extending radially from the bottom 22B toward the apex 22A of the particular notch 22 and / or the portion extending distally occupies a greater proportion of the depth of the particular notch 22, and preferably, the portion of the proximal surface 26 of the distal ridge segment 24D extending radially from the bottom 22B toward the apex 22A of the particular notch 22 and / or the portion extending proximally occupies a greater proportion of the depth of the particular notch 22. Specifically, the radial length of the distal surface 25 of the proximal ridge segment 24P, which extends radially from the bottom 22B of the specific notch 22 to the top 22A and / or 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 specific notch 22. The radial length of the proximal surface 26 of the distal ridge segment 24D, which extends radially from the bottom 22B of the specific notch 22 to the top 22A and / or 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 specific notch 22.

[0103] A drug layer 41 is provided in the specific notch 22. The provision of the drug layer 41 in this manner facilitates reliable delivery of the drug to the surface of the blood vessel wall without falling off during delivery of the balloon 10 to a treatment target site, such as a stenosis. The drug layer 41 provided in the specific notch 22 is protected by the distal surface 25 of the proximal ridge segment 24P and the proximal surface 26 of the distal ridge segment 24D, making it less likely to fall off from the specific notch 22 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 target site. Meanwhile, the drug layer 41 provided in the specific notch 22 is pushed up from the radially inner side by the balloon body 16 when the balloon 10 is inflated, thereby enabling delivery to the surface of the blood vessel wall.

[0104] As shown in FIG. 23 , at least one of the distal surface 25 of the proximal ridge segment 24P and the proximal surface 26 of the distal ridge segment 24D may be recessed. Specifically, the distal surface 25 of the proximal ridge segment 24P may be recessed proximally in a cross section along the outer surface of the balloon body 16, and the proximal surface 26 of the distal ridge segment 24D may be recessed distally in a cross section along the outer surface of the balloon body 16. The cross section 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, i.e., a cross section along the longitudinal axis and circumferential direction of the balloon 10. Note that the drug layer 41 is omitted in FIG. 23 . If the distal surface 25 of the proximal ridge segment 24P and / or the proximal surface 26 of the distal ridge segment 24D are formed in this manner, a larger amount of drug can be stably retained in a specific notch 22.

[0105] When the distal surface 25 of the proximal ridge segment 24P has a portion extending radially from the bottom 22B of the particular notch 22 to the apex 22A and / or a portion extending distally, and the proximal surface 26 of the distal ridge segment 24D has a portion extending radially from the bottom 22B of the particular notch 22 to the apex 22A and / or a portion extending proximally, a portion of the distal surface 25 of the proximal ridge segment 24P may be in contact with a portion of the proximal surface 26 of the distal ridge segment 24D (not shown). Forming the particular notch 22 in this manner can further enhance the scoring function of the ridge 21. In this case, it is preferable that at least a portion of the radially outer half of the distal surface 25 of the proximal ridge segment 24P be in contact with at least a portion of the radially outer half of the proximal surface 26 of the distal ridge segment 24D.

[0106] The ridges 21 are preferably formed so that, in a vertical cross section of the balloon 10 in the longitudinal axis direction, 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 Figure 26, the ridges 21 may be formed so that their width narrows in a stepped manner toward the apex 21A. In this case, it is sufficient that the ridges 21 have a portion that narrows in a stepped manner toward the apex 21A in at least a portion from the base 21B to the apex 21A.

[0107] Figures 24 to 26 show examples of the configuration of stepped ridges 21. Figure 24 shows a cross-sectional view of the ridge 21, which is a modification of the notch 22 of the ridge 21 shown in Figure 7, passing through the apex 21A of the ridge 21 and taken along the extension direction and radial direction of the ridge 21. Figure 25 shows a cross-sectional view of the ridge 21, which is a modification of the notch 22 of the ridge 21 shown in Figure 20, passing through the apex 21A of the ridge 21 and taken along the extension direction and radial direction of the ridge 21. Figure 26 shows a cross-sectional view XXVI-XXVI of the notch 22 of the ridge 21 shown in Figures 24 and 25. In Figures 24 to 26, the ridge 21 is formed to have a first step portion 31 adjacent to the outer surface of the balloon body 16 and a second step portion 32 closer to the apex 21A, as a portion whose width narrows in a stepwise manner toward the apex 21A. In this case, notch 22 of ridge 21 may be formed only in the portion on the top 21A side of stepped ridge 21; for example, notch 22 may be formed in second step portion 32 and not in first step portion 31. Drug layer 41 may be provided in notch 22 formed in second step portion 32. By providing drug layer 41 in notch 22 formed in this manner, drug layer 41 is more likely to be stably held in notch 22 of ridge 21.

[0108] Fig. 27 shows a configuration example in which cracks 43 are formed in drug layer 41 provided in notches 22 of ridges 21 shown in Fig. 24. In this case, it is preferable that cracks 43 are formed on the surface of drug layer 41 along bottoms 22B of notches 22 formed in second step portions 32.

[0109] The first step portion 31 and the second step portion 32 may be made of the same material or different materials. For example, the first step portion 31 and the second step portion 32 may both be made of resin, or the first step portion 31 may be made of metal and the second step portion 32 may be made of resin.

[0110] 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 41 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 41 can be selectively provided at desired locations on the surface of the balloon 10.

[0111] 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.

[0112] 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 41 on the surface of the ridges 21.

[0113] 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.

[0114] 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 41 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.

[0115] 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.

[0116] Figures 28 and 29 show an example of a configuration in which the balloon 10 shown in Figure 4 is deflated and folded. Figures 28 and 29 show cross-sectional views of the deflated balloon 10 cut perpendicular to the longitudinal axis direction at the notch 22 in the ridge 21. Also shown is an example in which a drug layer 41 is provided from the notch 22 to the ridge-free region 27, as shown in Figure 11.

[0117] 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 28 with the inner surface of the balloon body 16 facing inward, forming folded wing portions 29 where the non-ridge regions 28 overlap, and the folded wing portions 29 are disposed overlapping the outer surface of the balloon 10. The folded wing portions 29 are formed by folding back the non-ridge regions 28 of the balloon body 16 at the fold lines 30, with the non-ridge regions 28 overlapping each other. At the fold lines 30, the non-ridge regions 28 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 30 form a mountain fold. It is preferable that the folded wing portions 29 are formed only from the non-ridge regions 28 of the balloon body 16, and do not include the ridge regions 27.

[0118] The fold lines 30 are preferably formed so as to extend substantially parallel to the extension direction of the ridges 21. The non-ridge region 28 may be folded back so as to form a clear crease at the fold line 30, or may be folded back with a rounded tip. Note that, because the non-ridge region 28 of the balloon body 16 usually has a certain degree of thickness and elasticity, the non-ridge region 28 is folded back with a rounded tip at the fold line 30. In this case, when viewed in a vertical cross section of the balloon 10 in the longitudinal axis direction, the fold line 30 is the tip where the non-ridge region 28 is folded back.

[0119] It is preferable that the bending lines 30 are formed at least in the straight pipe section 13. Therefore, it is preferable that the balloon 10 has folding wing sections 29 formed by overlapping the ridge-free regions 28 in the straight pipe section 13, and that the folding wing sections 29 are arranged overlapping the outer surface of the straight pipe section 13.

[0120] The straight tube section 13 may have a fold line (a 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 30, 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 29.

[0121] Only one fold line 30 may be formed in each non-ridge-streak region 28, or two or more fold lines 30 may be formed in each non-ridge-streak region 28. Preferably, one or two fold lines 30 are formed in each non-ridge-streak region 28. In FIG. 28 , one fold line 30 is formed in each non-ridge-streak region 28, and in FIG. 29 , two fold lines 30 are formed in each non-ridge-streak region 28. When only one fold line 30 is formed in each non-ridge-streak region 28, it is preferable that the folding wings 29 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 30 are formed in each non-ridge-streak region 28, it is preferable that the two folding wings 29 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 29 when the balloon 10 is in a deflated state.

[0122] In one embodiment, when balloon 10 is in a deflated state, folding wings 29 may be arranged to cover apex 21A of ridge 21. In this case, drug layer 41 provided on end surface 22 of ridge 21 is protected by folding wings 29, making drug layer 41 less likely to fall off balloon 10 before balloon 10 is delivered to the treatment target area.

[0123] In another embodiment, when the balloon 10 is in a deflated state, the folding wings 29 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.

[0124] In Figure 28, one folding blade portion 29 is formed in one ridge-free region 28, and the folding blade portion 29 is arranged so as to cover the top 21A of the ridge 21, but in Figure 28, the folding blade portion 29 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 folding blade portions 29 are formed in one ridge-free region 28, and the folding blade portion 29 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 folding blade portion 29 may be arranged so as to cover the top 21A of the ridge 21.

[0125] This application claims the benefit of priority based on Japanese Patent Application Nos. 2024-010303 and 2024-010305 filed on January 26, 2024, Japanese Patent Application No. 2024-077680 filed on May 13, 2024, and Japanese Patent Application No. 2024-232072 filed on December 27, 2024. The entire contents of the specifications of Japanese Patent Application Nos. 2024-010303 and 2024-010305 filed on January 26, 2024, Japanese Patent Application No. 2024-077680 filed on May 13, 2024, and Japanese Patent Application No. 2024-232072 filed on December 27, 2024 are incorporated herein by reference.

[0126] 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: Convex rib, 21A: Apex, 21B: Base, 21S: Side surface 22: Notch, 22A: Apex, 22B: Bottom 23P: Proximal outer edge (of notch), 23D: Distal outer edge (of notch) 24: Convex rib segment, 24P: proximal convex rib segment, 24D: distal convex rib segment 25: distal surface (of proximal convex rib segment) 26: proximal surface (of distal convex rib segment) 27: Convex rib region 28: Convex rib non-existent region 29: Folding wing portion 30: Bending line 31: First step portion 32: Second step portion 41: Drug layer 42: Shortest point from the bottom of the notch in the convex rib to the surface of the drug layer 43: Crack 45: 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, a notch is formed in the ridge, and a drug layer is provided in the notch of the ridge.

2. The balloon according to claim 1, wherein the balloon has a straight tube portion, a proximal tapered portion located closer to the proximal side than the straight tube portion, and a distal tapered portion located closer to the distal side than the straight tube portion, and the drug layer is provided in the notch of the ridge in the straight tube portion.

3. The balloon according to claim 1, wherein the notch includes a specific notch provided with the drug layer that satisfies the following requirements. (Requirements) The outer surface of the balloon is divided into a ridge existing region and a ridge non-existing region, and in a cross section perpendicular to the longitudinal axis direction passing through the bottom of the specific notch, the average thickness of the drug layer in the specific notch is thicker than the average thickness of the drug layer in the ridge non-existing region.

4. The balloon according to claim 1, wherein the notch includes a specific notch that satisfies the following requirements. (Requirements) In a cross section along the extending direction and the radial direction of the ridge passing through the top of the ridge, at least a part of the proximal outer edge of the specific notch is located closer to the proximal side than a virtual straight line connecting the top and the bottom of the proximal outer edge of the specific notch, and / or at least a part of the distal outer edge of the specific notch is located closer to the distal side than a virtual straight line connecting the top and the bottom of the distal outer edge of the specific notch.

5. The balloon according to claim 1, wherein the notch includes a specific notch provided with the drug layer that satisfies the following requirements. (Requirements) In a cross section along the extending direction and the radial direction of the ridge passing through the top of the ridge, the surface of the drug layer provided in the specific notch is recessed inward in the radial direction, and the drug layer exists at the bottom of the specific notch.

6. The balloon according to claim 1, wherein the notch includes a specific notch provided with the drug layer satisfying the following requirements. (Requirement) In a cross section along the extending direction and the radial direction of the ridge passing through the top of the ridge, the shortest distance from the outer edge covered by the drug layer of the specific notch to the surface of the drug layer is the longest except at the bottom of the specific notch.

7. The balloon according to claim 1, wherein the notch includes a specific notch provided with the drug layer satisfying the following requirements. (Requirement) The proximal surface and / or the distal surface of the specific notch is formed to be recessed inward in the radial direction in a cross section perpendicular to the extending direction of the ridge.

8. The ridge is divided into a plurality of ridge segments by the notch, and the balloon according to claim 1, wherein the notch includes a specific notch provided with the drug layer satisfying the following requirements. (Requirement) In a cross section along the extending direction and the radial direction of the ridge passing through the top of the ridge, the distal surface of the ridge segment adjacent to the proximal side of the specific notch (hereinafter referred to as the "proximal side ridge segment") has a portion extending radially from the bottom to the top and / or a portion extending toward the distal side of the specific notch, and the proximal surface of the ridge segment adjacent to the distal side of the specific notch (hereinafter referred to as the "distal side ridge segment") has a portion extending radially from the bottom to the top and / or a portion extending toward the proximal side of the specific notch in the cross section.

9. The balloon according to claim 8, wherein a part of the distal surface of the proximal side ridge segment is in contact with a part of the proximal surface of the distal side ridge segment.

10. In a cross section perpendicular to the extending direction of the ridge, the ridge is formed to have a width narrowing stepwise toward the top of the ridge, and has a first step portion adjacent to the outer surface of the balloon body portion and a second step portion on the top side thereof, and the notch is formed in the second step portion and not in the first step portion. The balloon according to claim 1.

11. The balloon according to claim 1, wherein a crack extending along the bottom of the notch is formed on the surface of the drug layer.

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

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

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

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

16. The outer surface of the balloon is divided 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 main body facing inward, and a folded fin portion is formed by overlapping the rib absent regions. The folded fin portion is disposed so as to cover the outer surface of the balloon and cover the top of the rib. The balloon according to claim 1.

17. The outer surface of the balloon is divided 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 main body facing inward, and a folded fin portion is formed by overlapping the rib absent regions. The folded fin portion is disposed so as to cover the outer surface of the balloon and not cover the top of the rib. The balloon according to claim 1.

18. A balloon catheter comprising the balloon according to any one of claims 1 to 17.

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