Balloon catheter

Abstract

A balloon catheter comprising a balloon (10), wherein: the balloon (10) has a radially outwardly protruding ridge (21) on the outer surface thereof, and a ridge-present region (17) and a ridge-absent region (18) are formed on the outer surface of the balloon (10); the ridge (21) has a shape inclined toward one side in the circumferential direction in a vertical cross-section of the balloon (10) in the longitudinal axis direction in an expanded state; in a contracted state of the balloon (10), a folding blade (19) obtained by the ridge-absent region (18) overlapping itself is formed on the balloon (10); and the folding blade (19) tilts toward one side in the circumferential direction and overlaps the outer surface of the balloon (10).

Description

Balloon Catheter

[0001] The present disclosure relates to a balloon catheter.

[0002] It is known that various diseases occur when stenosis occurs in blood vessels, which are flow paths for blood circulation in the body, and blood circulation is impaired. In particular, when stenosis occurs in a coronary artery that supplies blood to the heart, it may cause serious diseases such as angina pectoris and myocardial infarction. As one of the methods for treating such a stenotic site in a blood vessel, there is angioplasty (such as PTA and PTCA) in which the stenotic site is dilated using a balloon catheter.

[0003] Balloon catheters provided with protruding ridges on the outer surface of the balloon are known (for example, Patent Documents 1 to 3). When such a balloon catheter is used, when the balloon is inflated, the protruding ridges provided on the balloon can be caused to bite into the stenotic site, and the stenotic site can be effectively dilated.

[0004] International Publication No. 2020 / 250611, Japanese Unexamined Patent Application Publication No. 2009-112361, Japanese Unexamined Patent Application Publication No. 2013-176507

[0005] A balloon provided with protruding ridges on its outer surface can exhibit a scoring function by means of the protruding ridges. For example, inflating the balloon at a calcified stenotic site can crack or split the calcified stenotic site. However, when inflating a balloon at a stenotic site with a high degree of stenosis, the protruding ridges hit the inner surface of the stenotic site when the balloon is not sufficiently inflated, so the protruding ridges may not hit the inner surface of the stenotic site directly, and the scoring function provided by the protruding ridges may not be sufficiently exhibited.

[0006] The problem to be solved by the present disclosure is to provide a balloon catheter capable of strongly pressing the inner surface of a stenotic site by means of the protruding ridges provided on the outer surface of the balloon when the balloon is inflated at the stenotic site, even when the balloon is not sufficiently inflated.

[0007] The balloon catheter according to the present disclosure that has been able to solve the above problems is as follows: [1] A balloon catheter having a balloon, wherein the balloon has a longitudinal axis direction and a radial and circumferential direction perpendicular to the longitudinal axis direction, and has a convex ridge projecting outward in the radial direction on the outer surface of the balloon, and a region with a convex ridge and a region without a convex ridge are formed on the outer surface of the balloon, in a vertical cross section in the longitudinal axis direction when the balloon is expanded, the convex ridge has a shape that is inclined to one side in the circumferential direction, and when the balloon is contracted, the balloon is folded back at the region without a convex ridge so that the regions without convex ridges overlap to form a folded wing portion, and the folded wing portion lies down to one side in the circumferential direction and is superimposed on the outer surface of the balloon. [2] The balloon catheter according to [1], wherein the folded wing portion is superimposed on the outer surface of the balloon so as to cover the top of the convex ridge. [3] The balloon catheter according to [1] or [2], wherein in a vertical cross-section in the longitudinal direction of the balloon in its expanded state, the width of the rib gradually decreases toward the radially outward direction. [4] The balloon catheter according to any one of [1] to [3], wherein in a vertical cross-section in the longitudinal direction of the balloon in its expanded state, the rib has a first side surface on one side and a second side surface on the other side in the circumferential direction, the entire first side surface is on the one side in the circumferential direction with respect to a virtual line connecting the midpoint of the base of the rib in the circumferential direction and the top of the rib, and the entire second side surface is on the other side in the circumferential direction with respect to the virtual line. [5] The balloon catheter according to any one of [1] to [4], wherein in a vertical cross-section in the longitudinal direction of the balloon in its expanded state, the angle between a virtual line connecting the midpoint of the base of the rib in the circumferential direction and the top of the rib and a line passing through the midpoint and extending radially is 10° or more and 45° or less. [6] The balloon catheter according to any one of [1] to [5], wherein in a vertical cross section in the longitudinal direction of the expanded balloon, the height of the protrusion is 0.5 times or more and 2.0 times or less the circumferential length of the base of the protrusion.[7] The balloon catheter according to any one of [1] to [6], wherein the balloon has a plurality of foldable fin portions, a plurality of protrusions are provided between the plurality of foldable fin portions that are adjacent to each other in the circumferential direction, and the protrusions provided between the plurality of foldable fin portions that are adjacent to each other in the circumferential direction are inclined toward the one side in the circumferential direction more than the protrusions provided toward the other side in the circumferential direction. [8] A balloon catheter equipped with a balloon, wherein the balloon has a longitudinal axis direction and a radial and circumferential direction perpendicular to the longitudinal axis direction, and has a protrusion projecting outward in the radial direction on the outer surface of the balloon, and the outer surface of the balloon has a region with a protrusion and a region without a protrusion, and in the contracted state of the balloon, the balloon is folded back at the region without a protrusion so that the regions without protrusions overlap to form a folded wing portion, the balloon is provided with a first protrusion and a second protrusion, the first protrusion has a shape that is inclined to one side in the circumferential direction in a cross section perpendicular to the longitudinal axis direction of the balloon, the second protrusion has a shape that is not inclined in the circumferential direction or is inclined to the other side in the circumferential direction in a cross section perpendicular to the longitudinal axis direction of the balloon, a plurality of folded wing portions are provided, and each of the plurality of folded wing portions lies down to one side in the circumferential direction and overlaps the outer surface of the balloon, A balloon catheter in which the first and second protrusions are provided between the plurality of circumferentially adjacent folded wing portions, and the second protrusion is positioned between the circumferentially adjacent folded wing portions, on the other side of the first protrusion in the circumferential direction.

[0008] According to the balloon catheter of this disclosure, when the balloon is expanded in a stenotic area, the protrusions provided on the outer surface of the balloon are more likely to come into direct contact with the inner surface of the stenotic area when the balloon is not fully expanded. Therefore, even when the balloon is not fully expanded, the protrusions can strongly compress the inner surface of the stenotic area, making it easier to expand the calcified stenotic area.

[0009] Figure 1 shows an example of the configuration of a balloon catheter according to an embodiment of the present disclosure, and represents a side view of the balloon catheter. Figure 1 shows a cross-sectional view taken along the line II-II of the balloon catheter shown in Figure 1. Figure 3 shows a cross-sectional view taken along the line III-III of the balloon catheter shown in Figure 1. Figure 4 shows a vertical cross-sectional view of the balloon in the longitudinal direction shown in Figure 4. Figure 5 shows a partially enlarged cross-sectional view of the convex ridge of the balloon shown in Figure 5. Figure 5 shows the balloon in a folded state, and represents a vertical cross-sectional view of the balloon in the longitudinal direction. Figure 4 shows another example of the balloon configuration, and represents a vertical cross-sectional view of the balloon in the longitudinal direction. Figure 8 shows the balloon in a folded state, and represents a vertical cross-sectional view of the balloon in the longitudinal direction. Figure 10 shows the balloon in a folded state, and represents a vertical cross-sectional view of the balloon in the longitudinal direction. Figure 12 shows the balloon in a folded state, and represents a vertical cross-sectional view of the balloon in the longitudinal direction. Figure 7 shows a schematic diagram illustrating the process of expanding a folded balloon from its folded state. The second diagram shows a schematic diagram illustrating the process of expanding a balloon with convex ridges that are not inclined in the circumferential direction, from its folded state.

[0010] The contents of this disclosure will be described in detail below based on the embodiments described below. However, the contents of this disclosure are not limited by the embodiments described below, and it is certainly possible to implement the disclosure with appropriate modifications to the extent that it is in line with the spirit of the preceding and following descriptions, and all such modifications are included within the technical scope of this disclosure. In addition, hatching and component reference numerals may be omitted in the drawings for convenience, in which case refer 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 to understand the features of this disclosure.

[0011] Examples of the configuration of a balloon catheter according to embodiments of the present disclosure will be described with reference to the drawings. Figures 1 to 4 show examples of the configuration of a balloon catheter equipped with a balloon according to the first embodiment of the present disclosure. Figure 1 is a side view of the balloon catheter, Figure 2 is a cross-sectional view taken along line II-II of the balloon catheter shown in Figure 1, Figure 3 is a cross-sectional view taken along line III-III of the balloon catheter shown in Figure 1, and Figure 4 is a perspective view of the balloon provided in the balloon catheter shown in Figure 1. Figure 1 shows an example of the configuration of a rapid exchange type balloon catheter.

[0012] The balloon catheter 1 has a balloon 10. Specifically, 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 end and a distal end, with the balloon 10 provided at the distal end of the shaft 2. The proximal end of the balloon catheter 1 refers to the direction toward the user (operator) relative to the extending direction of the balloon catheter 1, and the distal end refers to the opposite direction from the proximal end, i.e., the direction toward the target of treatment. The direction from the proximal end to the distal end of the balloon catheter 1 is also called the longitudinal axis direction.

[0013] The balloon catheter 1 is configured to supply fluid into the balloon 10 through the shaft 2, and the expansion and contraction of the balloon 10 can be controlled using an indefleror (balloon pressure / depressurization device). The fluid may be pressurized fluid pressurized by a pump or the like. Hereinafter, the fluid supplied into the balloon 10 will be referred to as the "balloon expansion fluid".

[0014] The shaft 2 is composed of, for example, an inner shaft 3 and an outer shaft 4. The inner shaft 3 is positioned within the lumen of the outer shaft 4. The inner shaft 3 can function as a passage for a guidewire that guides the advancement of the shaft 2, and when the balloon catheter 1 is used, the guidewire is inserted through the lumen of the inner shaft 3. The space between the inner shaft 3 and the outer shaft 4 can function as a passage for the balloon inflation fluid.

[0015] In the rapid exchange type balloon catheter 1, a guidewire port 7 is provided midway from the distal to the proximal end of the shaft 2. 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 part of the shaft 2, thereby forming a guidewire insertion passage that extends from the guidewire port 7 to the distal part of the shaft 2.

[0016] The outer shaft 4 may have a proximal outer shaft 4A and a distal outer shaft 4B, in which case it is preferable that the inner shaft 3 is positioned 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 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. The outer shaft 4 may not be divided into a proximal outer shaft 4A and a 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 be further made of multiple tube members.

[0017] It is preferable that a hub 5 is provided on the proximal side of the shaft 2. The hub 5 preferably has a fluid injection section 6 that communicates with the flow path of the balloon expansion fluid in the shaft 2. The balloon 10, shaft 2 (inner shaft 3, outer shaft 4), and hub 5 can be joined using conventionally known joining methods such as adhesives or heat welding.

[0018] Although not shown in the drawings, the balloon catheter may be an over-the-wire type balloon catheter in which the 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, it is preferable that the flow path for the balloon inflation fluid and the guidewire insertion passage provided in the shaft extend to the hub, and that the hub is configured to have a fluid injection section communicating with the flow path for the balloon inflation fluid and a treatment section communicating with the guidewire insertion passage. It is preferable that the hub has a bifurcated structure, with the fluid injection section provided on one of the bifurcated ends and the treatment section on the other.

[0019] 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.

[0020] The coating can be hydrophilic or hydrophobic 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 chemicals or additives.

[0021] Examples of hydrophilic coating agents include hydrophilic polymers such as polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, and methyl vinyl ether maleic anhydride copolymer, as well as hydrophilic coating agents made from any combination of these polymers.

[0022] Examples of hydrophobic coating agents include polytetrafluoroethylene (PTFE), fluoroethylene propylene (FEP), perfluoroalkoxyalkanes (PFA), silicone oil, hydrophobic urethane resins, carbon coatings, diamond coatings, diamond-like carbon (DLC) coatings, ceramic coatings, and substances with low surface free energy terminated with alkyl groups or perfluoroalkyl groups.

[0023] It is preferable that a tip 8 is provided at the distal end of the balloon catheter 1. The tip 8 may be provided as a separate component from the inner shaft 3 distal to the distal end of the inner shaft 3, or the distal end of the inner shaft 3 may function as the tip 8 by extending the inner shaft 3 distal to the distal end of the balloon 10.

[0024] The shaft 2 may have radiopaque markers 9 positioned in the portion where the balloon 10 is located in relation to the longitudinal axis, in order to allow confirmation of the balloon 10's position under X-ray fluoroscopy. The radiopaque markers 9 can be positioned, for example, on the inner shaft 3 located inside the balloon 10, preferably at positions corresponding to both ends of the straight section of the balloon 10, or at a position corresponding to the center of the straight section of the balloon 10.

[0025] The balloon 10 is formed in a cylindrical shape with a longitudinal axis direction and a radial direction, and openings on the proximal and distal ends. The longitudinal axis direction of the balloon 10 corresponds to the direction extending from the proximal to the distal end of the balloon catheter 1, and the radial direction of the balloon 10 is the direction perpendicular to the longitudinal axis direction, meaning the direction extending radially from the center of the balloon 10. The balloon 10 also has a circumferential direction perpendicular to the longitudinal axis direction. The circumferential direction of the balloon 10 is defined as the direction along the outer circumference of the expanded balloon 10 in a cross section perpendicular to the longitudinal axis direction of the balloon 10. The tubular membrane portion of the balloon 10 is referred to as the balloon body portion 16, and the balloon 10 has a tubular balloon body portion 16.

[0026] As shown in Figure 4, it is preferable that the balloon 10 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, with respect to the longitudinal axis. The straight tube section 13 is formed in a substantially cylindrical shape extending in the longitudinal axis 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 such that its outer diameter decreases as it moves away 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 such that its outer diameter decreases as it moves away from the straight tube section 13. Preferably, the balloon 10 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.

[0027] As described above, the balloon 10 is configured such that when the balloon 10 is expanded in the narrowed area, the straight tube portion 13 makes sufficient contact with the narrowed area, making it easier to perform treatments such as dilation of the narrowed area. Furthermore, because the balloon 10 has a proximal tapered portion 12 and a distal tapered portion 14, when the balloon 10 is deflated, the outer diameters of the proximal and distal ends of the balloon 10 can be reduced, thereby reducing the step difference between the shaft 2 and the balloon 10, making it easier to insert the balloon 10 into a body cavity, into the forceps channel of an endoscope, or into a delivery catheter such as a guiding catheter.

[0028] In the distal portion of the shaft 2, it is preferable that the inner shaft 3 extends distally from the distal end of the outer shaft 4, and that the inner shaft 3 extends through the internal space of the balloon 10 from the proximal sleeve portion 11 to the distal sleeve portion 15. Furthermore, it is preferable that the outer surface of the inner shaft 3 is joined to the inner surface of the distal sleeve portion 15 of the balloon 10, and the outer surface of the outer shaft 4 is joined to the inner surface of the proximal sleeve portion 11 of the balloon 10. With the distal portion of the shaft 2 configured in this way, the balloon expansion fluid can be supplied to the internal space of the balloon 10 through the space between the inner shaft 3 and the outer shaft 4.

[0029] The size of the balloon 10 is not particularly limited. For example, the size of the balloon 10 can be appropriately set within the range of 4 mm to 400 mm for the length in the longitudinal axis direction of the straight tube section 13 and 0.7 mm to 30 mm for the outer diameter of the straight tube section 13.

[0030] The balloon 10 (especially the balloon body 16) is preferably made of a resin, and more preferably of a thermoplastic resin. This makes it easier to manufacture the balloon 10 by molding. Examples of resins that make up 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; polyamide resins such as polyphenylene sulfide resin, polyamide, and polyamide elastomer; fluororesin, silicone resin, and natural rubber such as latex rubber. These may be used alone or in combination of two or more. Among these, polyamide resins, polyester resins, and polyurethane resins are preferably used. In particular, it is preferable to use elastomer resins from the viewpoint of thinning the balloon 10 and its flexibility. For example, among polyamide resins, nylon 12 and nylon 11 are suitable materials for the balloon 10, and nylon 12 is preferably used because it can be molded relatively easily when blow molding. Furthermore, from the viewpoint of thinning the balloon 10 and improving its flexibility, polyamide elastomers such as polyether ester amide elastomers and polyamide ether elastomers are preferably used. Among these, polyether ester amide elastomers are preferably used because they have high yield strength and good dimensional stability of the balloon 10.

[0031] The outer surface of the balloon 10 is provided with protrusions 21. The protrusions 21 are provided on the outer surface of the balloon 10, projecting radially outward. The protrusions 21 give the balloon 10 a scoring function, and when the balloon 10 is expanded in a lesion such as a narrowed part of a blood vessel, it can bite into the calcified lesion and cause a crack. Therefore, it is possible to expand the narrowed part while suppressing vascular dissection. It is also possible to increase the pressure resistance of the balloon 10 and suppress over-expansion when pressurized. Although the balloon 10 can also be used to treat lesions such as narrowed parts of body cavities other than blood vessels, the following explanation will focus on the application of the balloon 10 to vascular treatment.

[0032] The ridges 21 of the balloon 10 will be described in detail with reference to Figures 5 and 6. Figure 5 shows a vertical cross-sectional view of the straight pipe section 13 of the balloon 10 in the longitudinal direction, and Figure 6 shows an enlarged cross-sectional view of the ridges 21 provided on the outer surface of the balloon 10. Figure 5 shows an example of the configuration in the vertical cross-section of the straight pipe section 13 of the balloon 10 in the longitudinal direction shown in Figure 4, in which the ridges 21 are provided at three locations in the circumferential direction of the straight pipe section 13.

[0033] The balloon 10 has a balloon body portion 16, and a protrusion 21 is provided on the outer surface of the balloon body portion 16. The protrusion 21 is provided so as to project radially outward from the outer surface of the balloon body portion 16. As a result of the provision of the protrusion 21, a region 17 where the protrusion exists and a region 18 where the protrusion does not exist are formed on the outer surface of the straight tube portion 13 of the balloon 10. Notches may be formed in the protrusion 21.

[0034] In the balloon 10, the portion excluding the radially outwardly protruding ridge 21 becomes the balloon body portion 16. In a vertical cross-section along the longitudinal axis of the balloon 10, it is preferable that the outer shape of the balloon body portion 16 is substantially circular. In the straight tube portion 13, it is preferable that the outer surface of the balloon body portion 16 is cylindrical. The region 17 where the ridge exists is composed of the balloon body portion 16 and the ridge 21, and the region 18 where the ridge does not exist is composed of the balloon body portion 16.

[0035] The outer surface of the straight tube section 13 is preferably formed flat in the ridge-free region 18. For example, it is preferable that the outer surface of the straight tube section 13 is not formed with depressions in a part of the ridge-free region 18. This makes it easier to evenly expand the balloon 10 and makes it easier to achieve the scoring function of the ridges 21 as desired. Note that the outer surface of the straight tube section 13 being formed flat in the ridge-free region 18 means that the ridge-free region 18 is shaped like a plane that has been curved into an arch, and no irregularities are formed in the curved plane. This irregularity does not include surface roughness that is inevitably formed during manufacturing. It is also preferable that the outer surfaces of the proximal tapered section 12 and the distal tapered section 14 of the balloon 10 are formed flat in the ridge-free region 18.

[0036] The protrusion 21 has a top portion 22 and a base portion 23 (see Figure 6). In the protrusion 21, the top portion 22 refers to the tip of the protrusion 21, i.e., the outermost radial portion of the protrusion 21, and the base portion 23 refers to the boundary with the balloon body portion 16, i.e., the innermost radial portion of the protrusion 21.

[0037] The protrusions 21 can be made of, for example, resin. If the protrusions 21 are made of resin, the balloon 10 having the protrusions 21 can be manufactured by resin molding, making manufacturing easier. In this case, it is preferable that the protrusions 21 and the balloon body 16 are made of the same resin, and it is preferable that the protrusions 21 and the balloon body 16 are integrally molded. The balloon body 16 may have an inner layer and an outer layer, and in this case, it is preferable that the protrusions 21 are made of the same resin as the outer layer of the balloon body 16. This makes it less likely that the protrusions 21 will unintentionally detach from the balloon body 16. Alternatively, if the resin constituting the protrusions 21 and the resin constituting the balloon body 16 have a certain degree of compatibility, the protrusions 21 and the balloon body 16 may be made of different resins.

[0038] The protrusion 21 may be made of metal, or a combination of metal and resin. In this case, it is preferable that the portion of the protrusion 21 including the top 22 is made of metal. For example, the entire protrusion 21 may be made of metal, or the portion including the base 23 may be made of resin and the portion including the top 22 may be made of metal.

[0039] The ridges 21 are provided on the outer surface of the balloon 10 so as to extend in a ridge-like manner. Preferably, the ridges 21 are provided so as to extend in the longitudinal direction of the balloon 10. In this case, the ridges 21 may extend parallel to the longitudinal direction or diagonally to the longitudinal direction. In order to enhance the scoring function of the balloon 10 and to facilitate the manufacture of the balloon 10 having the ridges 21, it is preferable that the ridges 21 extend at an angle of ±30° or less with respect to the longitudinal direction, but it may also be at an angle of ±20° or ±15° or less. As the ridges 21 are provided so as to extend in the longitudinal direction of the balloon 10, the outer surface of the balloon 10 is divided in the circumferential direction into a region 17 where ridges exist and a region 18 where ridges do not exist.

[0040] It is preferable that the ridges 21 are provided at least on the straight tube portion 13. This makes it easier for the ridges 21 to penetrate deeply into the narrowed portion of the blood vessel when the balloon 10 is expanded, thereby enhancing the scoring function of the ridges 21. The ridges 21 may be provided in a range of 60% or more, 70% or more, or 80% or more in the longitudinal direction of the straight tube portion 13, thereby making it possible to create cracks over a wide area of ​​the narrowed portion when the balloon 10 is expanded. The ridges 21 may be provided in a range of 90% or more in the longitudinal direction of the straight tube portion 13, or they may be provided over almost the entire longitudinal direction of the straight tube portion 13. The ridges 21 may also be provided on the outer surface of the proximal tapered portion 12 and / or the distal tapered portion 14, and on the outer surface of the proximal sleeve portion 11 and / or the distal sleeve portion 15.

[0041] The protrusions 21 may be provided as a single or multiple in the vertical cross-section in the longitudinal direction of the balloon 10, but it is preferable that multiple protrusions be provided in the circumferential direction. That is, it is preferable that the protrusions 21 be provided at multiple locations in the circumferential direction of the balloon 10. This makes it possible to create cracks at multiple locations in the constricted section when the balloon 10 is expanded. The protrusions 21 may be provided at two or more or three or more locations in the circumferential direction of the balloon 10, or at 12 or fewer locations, 10 or fewer locations, or 8 or fewer locations.

[0042] In the balloon 10, it is preferable that the wall thickness of the portion provided with the ridges 21, that is, the wall thickness of the ridge-present region 17, is formed thicker than the wall thickness of the portion not provided with the ridges 21, that is, the wall thickness of the ridge-absent region 18. This can enhance the scoring function provided by the ridges 21. The (maximum) wall thickness of the ridge-present region 17 may be 1.5 times or more, 2.0 times or more, or 2.5 times or more of the (maximum) wall thickness of the ridge-absent region 18. The upper limit of the wall thickness of the ridge-present region 17 is not particularly limited, and may be, for example, 30 times or less, 20 times or less, or 10 times or less of the wall thickness of the ridge-absent region 18.

[0043] The balloon 10 may have inner ridges protruding radially inward on the inner surface of the balloon 10 (not shown). The ridges 21 and the inner ridges may be arranged at the same position relative to the longitudinal axial direction or the circumferential direction of the balloon 10, and they are preferably integrally formed, whereby a part of the balloon 10 may be formed to have a thicker wall.

[0044] The cross-sectional shape of the ridges 21, that is, the shape of the ridges 21 in a vertical cross-section along the longitudinal axial direction of the expanded balloon 10, will be described. The ridges 21 have a shape inclined toward one side in the circumferential direction. Hereinafter, the direction in which the ridges 21 are inclined in the circumferential direction is referred to as a first direction D1, and the opposite direction is referred to as a second direction D2. The first direction D1 and the second direction D2 in the circumferential direction of the balloon 10 are determined, for example, when the balloon 10 is viewed from the distal side.

[0045] In the balloon 10, the ridges 21 have a shape inclined in the first circumferential direction D1, and as will be described later, in the deflated state of the balloon 10, the folded blade portions 19 of the balloon 10 collapse in the first circumferential direction D1 and overlap the outer surface of the balloon 10. Accordingly, when expanding the balloon 10, the ridges 21 are likely to directly contact the inner surface of the stenosis when the balloon 10 is not sufficiently expanded, making it easy to expand the calcified stenosis by the ridges 21.

[0046] Examples of the cross-sectional shape of the ridge 21 include polygons such as triangles and pentagons, wedge shapes, convex shapes, spindle shapes, and other shapes inclined toward the first circumferential direction D1. Polygons include not only those with clear apexes at corners and straight sides, but also rounded-corner polygons with rounded corners, and those having at least a part of the sides formed as curved lines. The shape of the ridge 21 inclined toward the first circumferential direction D1 only needs to be such that the apex 22 of the ridge 21 is located closer to the first circumferential direction D1 than the circumferential midpoint 24 of the base 23 of the ridge 21 is.

[0047] As shown in Fig. 6, in a vertical cross-section along the longitudinal axial direction of the balloon 10 in an expanded state, the angle θ formed between an imaginary straight line L1 connecting the circumferential midpoint 24 of the base 23 of the ridge 21 and the apex 22 of the ridge 21, and a straight line L0 extending in the radial direction passing through the midpoint 24, is preferably not less than 10° and not more than 45°. The angle θ may be not less than 15°, and may be not more than 40° or not more than 35°. This makes it easy for the ridges 21 to abut against the inner surface of the stenosis from the front when expanding the balloon 10.

[0048] In a vertical cross-section along the longitudinal axial direction of the balloon 10 in an expanded state, the width of the ridge 21 preferably gradually decreases toward the radially outward side. When the ridge 21 is formed in this manner, the ridge 21 can strongly compress the inner surface of the stenosis when the balloon 10 is expanded.

[0049] In a vertical cross-section along the longitudinal axial direction of the balloon 10 in an expanded state, the ridge 21 has a first side surface 25 on the first circumferential direction D1 side and a second side surface 26 on the second circumferential direction D2 side. It is preferable that the entire first side surface 25 is located on the first circumferential direction D1 side relative to the imaginary straight line L1, and the entire second side surface 26 is located on the second circumferential direction D2 side relative to the imaginary straight line L1. When the ridge 21 is formed in this manner, the ridge 21 is less likely to bend when the balloon 10 is expanded, making it easy for the ridge 21 to suitably expand the inner surface of the stenosis.

[0050] In a vertical cross-section along the longitudinal axis of the expanded balloon 10, the height (radial length) of the ridge 21 is preferably 0.5 times or more the circumferential length of the base 23 of the ridge 21. When the ridge 21 is formed in this way, when the balloon 10 is expanded, the ridge 21 is more likely to bite into the inner surface of the constricted portion, thereby enhancing the scoring function of the ridge 21. The height of the ridge 21 may be 0.6 times or more, or 0.7 times or more, the circumferential length of the base 23 of the ridge 21. On the other hand, the height of the ridge 21 may be 2.0 times or less, 1.8 times or less, or 1.5 times or less, the circumferential length of the base 23 of the ridge 21. This makes it less likely for the ridge 21 to bend when it comes into contact with the inner surface of the constricted portion.

[0051] As described above, the balloon 10 has a convex ridge 21 formed on its outer surface, and is then deflated and folded. When the balloon 10 is folded, its radial size is reduced, making it easier to insert into a guiding catheter or sheath and deliver it to the target area for treatment, such as a narrowed part of a blood vessel.

[0052] Figure 7 shows an example of a configuration in which the balloon 10 shown in Figure 5 is deflated and folded. As shown in Figure 7, in the deflated state of the balloon 10, the balloon 10 is folded back at the non-ridge region 18, forming a folded wing portion 19 where the non-ridge regions 18 overlap, and the folded wing portion 19 lies down and overlaps the outer surface of the balloon 10. The folded wing portion 19 is formed by folding the balloon 10 with its inner surface facing inward, and more specifically, by folding back the balloon body portion 16, which is a tubular membrane portion of the balloon 10, with its inner surface facing inward. The folded wing portion 19 is formed when the balloon body portion 16 is folded back at the fold line 20 of the non-ridge region 18, and the non-ridge regions 18 overlap. It is preferable that the folded wing portion 19 is formed without including the ridge region 17. When viewed from the outside of the balloon 10, the fold line 20 is formed as a mountain fold.

[0053] At the fold line 20, the balloon body portion 16 may be folded back so as to form a clear crease, or its tip may be folded back in a rounded shape. Since the balloon body portion 16 usually has a certain thickness and elasticity, the tip of the balloon body portion 16 is folded back in a rounded shape at the fold line 20. In this case, the folded tip of the balloon body portion 16 becomes the fold line 20.

[0054] It is preferable that the fold line 20 is formed at least on the straight tube portion 13. Therefore, it is preferable that the balloon 10 has a foldable fin portion 19 formed on the straight tube portion 13, and that the foldable fin portion 19 is arranged to overlap the outer surface of the straight tube portion 13.

[0055] The folding line 20 is preferably formed to extend parallel to the longitudinal axis or diagonally with respect to the longitudinal axis. Furthermore, it is preferable that multiple folding fin portions 19 are provided on the outer surface of the balloon 10. By forming the folding fin portions 19 in this way, it becomes easier to fold the balloon 10 compactly.

[0056] The balloon 10 may have fold lines formed on one and / or the other side in the circumferential direction of the fold line 20, with the outer surface of the balloon 10 folded inward (valley fold lines when viewed from the outside of the balloon 10). In this case, it is preferable that the fold lines that become valley fold lines form the base of the folded wing portion 19.

[0057] The folded fin portion 19 is bent over in the first circumferential direction D1. That is, the direction in which the convex 21 is installed at an angle on the outer surface of the balloon 10 and the direction in which the folded fin portion 19 is bent over in the contracted state of the balloon 10 are both the first circumferential direction D1. As a result, when the balloon 10 is expanded, the convex 21 is more likely to come into direct contact with the inner surface of the constricted area when the balloon 10 is not fully expanded, and the top 22 of the convex 21 is more likely to strongly compress the inner surface of the constricted area. Therefore, even in the case of a highly calcified constricted area, it becomes easier to expand the constricted area with the balloon 10. If the constricted area is highly calcified, it is difficult to apply high stress to the constricted area when the balloon 10 is not fully expanded, and there is a risk that the calcified constricted area cannot be expanded by the balloon 10. However, if the ridge 21 has a shape inclined in the first circumferential direction D1, and the folded wing portion 19 is bent over in the first circumferential direction D1, then when the balloon 10 is expanded, the ridge 21 is more likely to come into direct contact with the inner surface of the constricted portion before the balloon 10 is fully expanded. As a result, the expansion pressure of the balloon 10 is concentrated at the top 22 of the ridge 21, and the ridge 21 can strongly compress the inner surface of the constricted portion, thereby applying high stress to the constricted portion. This makes it easier to crack or expand the calcified constricted portion with the ridge 21, even before the balloon 10 is fully expanded. This will be explained with reference to Figures 14 and 15.

[0058] Figure 14 shows the results of a simulation of the intermediate stages of expansion of the balloon 10 shown in Figure 7, from a folded state to a narrowed blood vessel. For comparison, Figure 15 shows the results of a simulation of the intermediate stages of expansion of the balloon 10, which has convex ridges 41 that are not inclined in the circumferential direction, from a folded state to a narrowed blood vessel. Figures 14 and 15 show the initial state of expansion of the balloon 10.

[0059] As shown in Figure 15, when a balloon 10 equipped with ridges 41 that are not inclined in the circumferential direction is expanded in a constricted area, if the balloon 10 is not fully expanded, the sides of the ridges 41 tend to contact the inner surface of the constricted area rather than the tops of the ridges 41. Therefore, in the initial state of expansion of the balloon 10, it is not possible to strongly compress the inner surface of the constricted area, making it difficult to apply high stress to the constricted area. If the constricted area is highly calcified, the balloon 10 may not be able to expand the calcified constricted area, and there is a risk that the balloon 10 itself may not be able to expand further.

[0060] On the other hand, in Figure 14, the convex rib 21 has a shape that is inclined in the same direction as the direction in which the folded wing portion 19 collapses. Therefore, when the balloon 10 is expanded in the constricted portion, the convex rib 21 is more likely to come into direct contact with the inner surface of the constricted portion before the balloon 10 has fully expanded. As a result, the convex rib 21 can strongly compress the inner surface of the constricted portion before the balloon 10 has fully expanded, and a high stress can be applied to the constricted portion. According to the inventors' studies, the balloon 10 shown in Figure 14 can increase the stress applied to the constricted portion in the initial expansion state by about twice as much as the balloon 10 shown in Figure 15.

[0061] Although the balloon 10 described above had one protrusion 21 between circumferentially adjacent folded fin portions 19, multiple protrusions 21 may be provided between circumferentially adjacent folded fin portions 19. For example, the balloon 10 may have multiple folded fin portions 19, and multiple protrusions 21 may be provided between multiple circumferentially adjacent folded fin portions 19. This will be explained with reference to Figures 8 and 9.

[0062] Figures 8 and 9 show examples of the balloon configuration according to the second embodiment of this disclosure. Figure 8 shows the balloon in an expanded state, representing a vertical cross-sectional view in the longitudinal direction of the balloon, and Figure 9 shows the balloon shown in Figure 8 in a folded state, representing a vertical cross-sectional view in the longitudinal direction of the balloon. In the description of the balloon of the second embodiment, descriptions that overlap with those of the balloon of the first embodiment will be omitted.

[0063] In the balloon 10 according to the second embodiment, a plurality of protrusions 21 are provided between circumferentially adjacent folded wing portions 19. In this case, it is preferable that the protrusions 21 located on one side in the circumferential direction are inclined toward that side in the circumferential direction more than the protrusions 21 located on the other side in the circumferential direction. In Figure 9, two protrusions 21, protrusions 21a and protrusions 21b, are provided between circumferentially adjacent folded wing portions 19, and the protrusion 21a located on the side of the first circumferential direction D1 is inclined toward the first circumferential direction D1 more than the protrusion 21b located on the side of the second circumferential direction D2. When a constricted area is expanded using such a balloon 10, the protrusions 21a are more likely to hit the inner surface of the constricted area from the front when the balloon 10 is not fully expanded, and then the protrusions 21b are more likely to hit the inner surface of the constricted area from the front when the balloon 10 is further expanded. Therefore, the constricted area can be effectively widened by the protrusions 21a and 21b not only when the balloon 10 is not fully expanded but also when it is fully expanded. The protrusions 21a and 21b may be spaced apart in the circumferential direction, or they may be in contact with each other in the circumferential direction.

[0064] The outer surface of the balloon 10 may be provided with protrusions other than the protrusions 21 described above. That is, in the vertical cross-section in the longitudinal direction of the balloon 10, there may be protrusions that are not inclined in the circumferential direction, or that are inclined toward the second circumferential direction D2. This will be explained with reference to Figures 10 to 13.

[0065] Figures 10 and 11 show examples of balloon configurations according to the third embodiment. Figure 10 shows the balloon in an expanded state, representing a vertical cross-sectional view along the longitudinal axis of the balloon, and Figure 11 shows the balloon shown in Figure 10 in a folded state, representing a vertical cross-sectional view along the longitudinal axis of the balloon. Figures 12 and 13 show examples of balloon configurations according to the fourth embodiment. Figure 12 shows the balloon in an expanded state, representing a vertical cross-sectional view along the longitudinal axis of the balloon, and Figure 13 shows the balloon shown in Figure 12 in a folded state, representing a vertical cross-sectional view along the longitudinal axis of the balloon. Note that in the descriptions of the balloons of the third and fourth embodiments, descriptions that overlap with those of the balloon of the first embodiment will be omitted.

[0066] The balloon 10 of the third and fourth embodiments has a plurality of protrusions 31 on its outer surface. The configuration of the balloon 10 of the third and fourth embodiments is the same as that of the balloon 10 of the first embodiment, except for the protrusions 31. The configuration of the protrusions 31 is the same as that of the protrusions 21, except for the cross-sectional shape. The configuration related to folding the balloon 10 of the third and fourth embodiments also refers to the description of folding the balloon 10 of the first embodiment.

[0067] The balloon 10 in the third and fourth embodiments is provided with a first convex ridge 32 and a second convex ridge 33 as convex ridges 31. The first convex ridge 32 has a shape that is inclined toward the first circumferential direction D1 in a vertical cross section in the longitudinal axis direction of the balloon 10, and corresponds to the convex ridge 21 in the balloon 10 of the first embodiment. The second convex ridge 33 has a shape that is not inclined toward the circumferential direction or is inclined toward the second circumferential direction D2 in a vertical cross section in the longitudinal axis direction of the balloon 10, and the second convex ridge 33 is positioned between adjacent circumferential folding wing portions 19 on the side of the first convex ridge 32 toward the second circumferential direction D2. In Figures 10 and 11, the second convex ridge 33 has a shape that is inclined toward the second circumferential direction D2, while in Figures 12 and 13, the second convex ridge 33 has a shape that is not inclined toward the circumferential direction. The first convex ridge 32 and the second convex ridge 33 may be provided separated in the circumferential direction or in contact with each other in the circumferential direction.

[0068] When the constricted area is expanded with the balloon 10 shown in Figures 10 and 11, the first protrusion 32 is more likely to come into direct contact with the inner surface of the constricted area when the balloon 10 is not yet fully expanded, making it easier for the balloon 10 to expand the constricted area. Further expansion of the balloon 10 allows the first protrusion 32 and the second protrusion 33 to work together to widen the constricted area, and this state can be stably maintained.

[0069] When the constricted area is expanded with the balloon 10 shown in Figures 12 and 13, the first protrusion 32 is more likely to come into direct contact with the inner surface of the constricted area when the balloon 10 is not yet fully expanded, making it easier for the balloon 10 to expand the constricted area. Further expansion of the balloon 10 makes it easier for the second protrusion 33 to come into direct contact with the inner surface of the constricted area, making it easier to compress and effectively expand the constricted area with the second protrusion 33.

[0070] Details of the first ridge 32 are described in the above description of the ridge 21. The second ridge 33 is preferably such that its width gradually decreases radially outward in a vertical cross-section along the longitudinal axis when the balloon 10 is expanded. In a vertical cross-section along the longitudinal axis when the balloon 10 is expanded, the height of the second ridge 33 may be 0.5 times or more, 0.6 times or more, or 0.7 times or more the circumferential length of the base of the second ridge 33, or it may be 2.0 times or less, 1.8 times or less, or 1.5 times or less.

[0071] In a vertical cross-section of the balloon 10 in its expanded state along the longitudinal axis, the second protrusion 33 has a first side surface on the circumferential first direction D1 side and a second side surface on the circumferential second direction D2 side, and it is preferable that the entire first side surface lies on the circumferential first direction D1 side with respect to a virtual line connecting the midpoint of the circumferential base of the second protrusion 33 and the top of the second protrusion 33, and the entire second side surface lies on the circumferential second direction D2 side with respect to the said virtual line.

[0072] In the third embodiment, in a vertical cross-section in the longitudinal direction of the expanded balloon 10, it is preferable that the angle between the imaginary straight line connecting the midpoint of the circumferential direction of the base of the second protrusion 33 and the apex of the second protrusion 33 and the straight line extending radially through the midpoint is 45° or less, but it may be 40° or less or 35° or less.

[0073] As shown in Figures 3 to 9, the outer surface of the balloon 10 may be provided with only a convex ridge 21 having a shape inclined in the first circumferential direction D1. That is, the outer surface of the balloon 10 may be provided with a convex ridge 21 having a shape inclined in the first circumferential direction D1, and may not be provided with a convex ridge that is not inclined in the circumferential direction or that is inclined toward the second circumferential direction D2. Also, as shown in Figures 11 and 12, the outer surface of the balloon 10 may be provided with only a first convex ridge 32 having a shape inclined in the first circumferential direction D1 and a second convex ridge 33 having a shape inclined toward the second circumferential direction D2. As shown in Figures 13 and 14, the outer surface of the balloon 10 may be provided with only a first convex ridge 32 having a shape inclined in the first circumferential direction D1 and a second convex ridge 33 having a shape that is not inclined in the circumferential direction.

[0074] The outer surface of the balloon 10 may contain a drug. In angioplasty, restenosis may occur in the narrowed area expanded by the balloon 10. However, if a drug is provided on the outer surface of the balloon 10, the drug can be moved to the inner wall of the body cavity, such as the blood vessel wall, by expanding the balloon 10 in the narrowed area of ​​the blood vessel, thereby reducing the frequency of restenosis.

[0075] The drugs are not particularly limited as long as they are pharmacologically active substances, and include, for example, gene therapy drugs, non-gene therapy drugs, small molecules, cells, and other drugs that are accepted as pharmaceuticals. In particular, when catheters are used to suppress restenosis of blood vessels after treatment in angioplasty, anti-restenotic agents such as antiproliferative agents and immunosuppressants can be preferably used as drugs. Examples of such drugs include paclitaxel, sirolimus (rapamycin), everolimus, and zotarolimus.

[0076] This application claims the benefit of priority based on Japanese Patent Application No. 2025-051222, filed on 26 March 2025. The entire specification of Japanese Patent Application No. 2025-051222, filed on 26 March 2025, is incorporated herein by reference.

[0077] 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: Tip 9: Radiopaque marker 10: Balloon 11: Proximal sleeve section 12: Proximal tapered section 13: Straight section 14: Distal tapered section 15: Distal sleeve section 16: Balloon body section 17: Area with protrusions 18: Area without protrusions 19: Folding fin section 20: Folding line 21, 21a, 21b: Protrusions 22: Top 23: Base 24: Midpoint 25: First side 26: Second side 31: Protrusion 32: First protrusion 33: Second protrusion D1: First direction (circumferential) D2: Second direction (circumferentially)

Claims

1. A balloon catheter having a balloon, wherein the balloon has a longitudinal axis direction and a radial and circumferential direction perpendicular to the longitudinal axis direction, and has a convex ridge projecting outward in the radial direction on the outer surface of the balloon, and the outer surface of the balloon has a region with a convex ridge and a region without a convex ridge formed thereon, in a vertical cross section in the longitudinal axis direction when the balloon is expanded, the convex ridge has a shape inclined to one side in the circumferential direction, and when the balloon is contracted, the balloon is folded back at the region without a convex ridge to form a folded wing portion where the regions without convex ridges overlap, and the folded wing portion lies down to one side in the circumferential direction and overlaps the outer surface of the balloon.

2. The balloon catheter according to claim 1, wherein the folded wing portion is superimposed on the outer surface of the balloon so as to cover the top of the convex ridge.

3. The balloon catheter according to claim 1, wherein, in the longitudinal axial direction of the expanded balloon, the width of the protrusions gradually decreases toward the radially outward direction.

4. The balloon catheter according to any one of claims 1 to 3, wherein, in a vertical cross-section in the longitudinal direction of the expanded balloon, the protrusion has a first side surface on one side and a second side surface on the other side in the circumferential direction, the entire first side surface is on the one side in the circumferential direction with respect to a virtual line connecting the midpoint of the base of the protrusion in the circumferential direction and the apex of the protrusion, and the entire second side surface is on the other side in the circumferential direction with respect to the virtual line.

5. The balloon catheter according to any one of claims 1 to 3, wherein, in a vertical cross-section in the longitudinal direction of the balloon in its expanded state, the angle between a virtual straight line connecting the midpoint of the circumferential direction of the base of the protrusion and the apex of the protrusion and a straight line passing through the midpoint and extending in the radial direction is 10° or more and 45° or less.

6. The balloon catheter according to any one of claims 1 to 3, wherein in a vertical cross-section in the longitudinal direction of the expanded balloon, the height of the protrusion is 0.5 times or more and 2.0 times or less the circumferential length of the base of the protrusion.

7. The balloon catheter according to any one of claims 1 to 3, wherein the balloon has a plurality of foldable fin portions, a plurality of protrusions are provided between the plurality of foldable fin portions that are adjacent in the circumferential direction, and the plurality of protrusions provided between the circumferentially adjacent foldable fin portions are inclined toward the one side in the circumferential direction more than the protrusions provided toward the other side in the circumferential direction.

8. A balloon catheter equipped with a balloon, wherein the balloon has a longitudinal axis direction and a radial and circumferential direction perpendicular to the longitudinal axis direction, and has a convex ridge projecting outward in the radial direction on the outer surface of the balloon, and the outer surface of the balloon has a region with a convex ridge and a region without a convex ridge, and in the contracted state of the balloon, the balloon is folded back at the region without a convex ridge to form a folded wing portion where the regions without convex ridges overlap, the balloon is provided with a first convex ridge and a second convex ridge, the first convex ridge has a shape that is inclined to one side in the circumferential direction in a cross section perpendicular to the longitudinal axis direction of the balloon, the second convex ridge has a shape that is not inclined in the circumferential direction or is inclined to the other side in the circumferential direction in a cross section perpendicular to the longitudinal axis direction of the balloon, a plurality of folded wing portions are provided, and each of the plurality of folded wing portions lies down to one side in the circumferential direction and overlaps the outer surface of the balloon, A balloon catheter in which the first and second protrusions are provided between the plurality of circumferentially adjacent folded wing portions, and the second protrusion is positioned between the circumferentially adjacent folded wing portions, on the other side of the first protrusion in the circumferential direction.

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