Balloon for balloon catheter

Abstract

Provided is a balloon that can improve trackability and protect the expansion part of the balloon while the balloon is being transported in a contracted state within a body cavity.　A balloon (2) for a balloon catheter has a balloon main body (27) and an outside protruding part (60) and satisfies (1) and / or (2) below when the balloon (2) is in a contracted state.　(1) The radius r1 of a first imaginary cylinder C1 circumscribed by a proximal sleeve part (21) is larger than the radius r0 of an imaginary circle C0 circumscribed by an expansion part (20) at the center (20c) of the expansion part (20).　(2) The radius r2 of a second imaginary cylinder C2 circumscribed by a distal sleeve part (22) is larger than the radius r0 of the imaginary circle C0 circumscribed by the expansion part (20) at the center (20c) of the expansion part (20).

Description

Technical Field

[0001] The present invention relates to a balloon for a balloon catheter.

Background Art

[0002] When a stenosis formed by calcification or the like occurs on the inner wall of a blood vessel, diseases such as angina pectoris and myocardial infarction are caused. As one of these treatments, there is an angioplasty in which a stenosis is expanded using a balloon catheter. Angioplasty is a minimally invasive treatment that does not require thoracotomy such as bypass surgery and is widely performed.

[0003] In angioplasty, it may be difficult to expand a stenosis hardened by calcification or the like with a general balloon catheter. In addition, a method of expanding a stenosis by implanting an implantable expansion device called a stent in the stenosis is also used. However, in some cases, ISR (In-Stent-Restenosis) lesions or the like may occur in which the neointima of the blood vessel grows excessively after this treatment and the blood vessel stenosis occurs again. In ISR lesions, the neointima is soft and the surface is slippery. Therefore, with a general balloon catheter, the position of the balloon may shift from the lesion during balloon expansion, damaging the blood vessel.

[0004] Even for such calcified lesions and ISR lesions, balloon catheters capable of dilating the stenotic portion have been developed, in which protrusions, blades, and scoring elements for biting into the stenotic portion are provided on the balloon. For example, Patent Document 1 discloses a balloon catheter having a scoring element made of a polymer material with higher rigidity than the polymer material forming the balloon body, and the scoring element is flattened at one end and the other end of the balloon. Patent Document 2 discloses a scoring balloon structure in which the height of the scoring element decreases along the tapered shape of the balloon. Patent Document 3 discloses a balloon catheter in which an outer protrusion is provided on the straight tube portion of the balloon and an inner protrusion is provided on the tapered portion. In Patent Documents 1 to 3 above, the height of the scoring element decreases at both ends of the balloon, or an inner protrusion is provided instead of an outer protrusion. On the other hand, there is also a balloon catheter in which the protrusion amount of the protrusion arranged on the distal tapered portion is larger than that of the protrusion arranged on the straight tube portion of the balloon (Patent Document 4).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0006] A balloon catheter is inserted into a body cavity in a contracted and folded state and delivered to a treatment site. Therefore, in the balloon catheters disclosed in Patent Documents 1 to 3 above, in order to be easily inserted into the body cavity, the height of the scoring element at the tip of the balloon is suppressed to prevent the outer diameter from increasing, and an attempt is made to improve the passageability of the balloon. However, in such a balloon catheter, since the height of the scoring element is suppressed at both ends of the balloon, the expansion part of the balloon comes into contact with the body cavity wall during the delivery of the balloon, and the contact area between the balloon and the body cavity wall during delivery increases. As a result, there is a risk of a decrease in the trackability of the balloon (the ease with which the balloon follows the curvature of the body cavity during balloon conveyance in the body cavity) in the curved part of the body cavity. In addition, since the balloon is conveyed to the lesion part while the expansion part of the balloon is in contact with the body cavity wall, there is also a case where the expansion part of the balloon that is expanded during treatment and acts on the lesion part is damaged during conveyance, hindering the treatment. In the balloon catheter disclosed in Patent Document 4 above, the height of the protruding part arranged in the tip-side tapered part is increased for the purpose of facilitating incision into the lesion part in the expanded state, but there is room for improvement in terms of improving the trackability when conveying the contracted balloon to the lesion part and protecting the balloon expansion part during conveyance.

[0007] In view of the above circumstances, an object of the present invention is to provide a balloon for a balloon catheter that can improve trackability and protect the expansion part of the balloon when conveying a contracted balloon in a body cavity.

Means for Solving the Problems

[0008] One embodiment of the balloon for a balloon catheter of the present invention that can solve the above problems has an expansion part, a proximal sleeve part located closer to the proximal side than the expansion part, and a distal sleeve part located farther from the distal side than the expansion part. A balloon for a balloon catheter having a balloon body having an outer surface and an inner surface, and an outer protruding part protruding radially outward from the outer surface of the balloon body and extending in the longitudinal axis direction of the balloon body. In the contracted state of the balloon, at least one of the following (1) and (2) is satisfied. (1) The radius of the first virtual cylinder C1 having a central axis parallel to the longitudinal axis direction, the bottom surface of which is located at the distal end and the proximal end of the proximal sleeve part, and at least a part of the side surface of which the proximal sleeve part is circumscribed, is the radius of the virtual circle C0 circumscribed by the expansion part in the radial cross section perpendicular to the longitudinal axis direction at the midpoint in the longitudinal axis direction of the expansion part. bigger. (2) The radius of the second virtual cylinder C2 having a central axis parallel to the longitudinal axis direction, the bottom surface of which is located at the distal end and the proximal end of the distal sleeve part, and at least a part of the side surface of which the distal sleeve part is circumscribed, is the radius of the virtual circle C0 circumscribed by the expansion part in the radial cross section perpendicular to the longitudinal axis direction at the midpoint in the longitudinal axis direction of the expansion part. bigger.

[0009] The expansion part has a main section excluding 10% each from the distal end and the proximal end in the longitudinal axis direction, and in the contracted state of the balloon, it is preferable that at least one of the following (1) and (2) is satisfied. (1) The radius of the first virtual cylinder C1 is larger than the radius of the third virtual cylinder C3 having a central axis parallel to the longitudinal axis direction, the bottom surface of which is located at the distal end and the proximal end of the main section, and at least a part of the side surface of which the main section is circumscribed. (2) The radius of the second virtual cylinder C2 is larger than the radius of the third virtual cylinder C3 having a central axis parallel to the longitudinal axis direction, the bottom surface of which is located at the distal end and the proximal end of the main section, and at least a part of the side surface of which the main section is circumscribed.

[0010] In the contracted state of the balloon, the balloon is preferably folded.

[0011] The outer protrusion has a tip portion in the radial cross section, and in the contracted state of the balloon, it preferably satisfies at least one of the following (1) and (2). (1) In the proximal sleeve portion, the tip portion is circumscribed to at least a part of the side surface of the first virtual cylinder C1. (2) In the distal sleeve portion, the tip portion is circumscribed to at least a part of the side surface of the second virtual cylinder C2.

[0012] The outer protrusion has a tip portion in the radial cross section, and in the contracted state of the balloon, it preferably satisfies at least one of the following (1) and (2). (1) In the proximal sleeve portion, only the tip portion is circumscribed to at least a part of the side surface of the first virtual cylinder C1. (2) In the distal sleeve portion, only the tip portion is circumscribed to at least a part of the side surface of the second virtual cylinder C2.

[0013] In the contracted state of the balloon, it is preferable that the expansion portion has vanes and the vanes are circumscribed to the virtual circle C0.

[0014] In the contracted state of the balloon, it is preferable that the expansion portion has vanes and the outer protrusion is arranged other than the vanes.

[0015] It preferably satisfies at least one of the following (1) and (2). (1) The outer protrusions of the proximal sleeve portion and the expansion portion are continuously extended in the longitudinal axis direction. (2) The outer protrusions of the distal sleeve portion and the expansion portion are continuously extended in the longitudinal axis direction.

[0016] In the contracted state of the balloon, it is preferable that the radius of the first virtual cylinder C1 in the proximal sleeve portion is larger than the radius of the virtual circle C0 in the expansion portion, and the radius of the second virtual cylinder C2 in the distal sleeve portion is smaller than the radius of the virtual circle C0. In this case, the expansion portion has a main section excluding 10% each from the distal end and the proximal end in the longitudinal axis direction. In the contracted state of the balloon, the radius of the first virtual cylinder C1 in the proximal sleeve portion is larger than the radius of a third virtual cylinder C3 having a central axis parallel to the longitudinal axis direction and whose bottom surface is located at the distal end and the proximal end of the main section and at least a part of the side surface is circumscribed by the main section. It is preferable that the radius of the second virtual cylinder C2 in the distal sleeve portion is smaller than the radius of the third virtual cylinder C3. Further, in this case, it is preferable that the distal sleeve portion has an inner protruding portion that protrudes radially inward from the inner surface of the balloon body and extends in the longitudinal axis direction.

[0017] The outer protruding portion is preferably made of the same material as the balloon body.

Advantages of the Invention

[0018] According to the balloon for the balloon catheter described above, in the contracted state of the balloon, since the radius of the virtual cylinder circumscribing at least one of the proximal sleeve portion and the distal sleeve portion is larger than the radius of the virtual circle circumscribing the central portion of the expansion portion, when transporting the contracted balloon in the body cavity, the trackability of the balloon can be improved and the expansion portion of the balloon can be protected.

Brief Description of the Drawings

[0019]

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DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, the present invention will be specifically described based on embodiments. However, the present invention is not limited by the following embodiments, and it is of course possible to appropriately modify and implement it within a range that conforms to the gist of the foregoing and following descriptions, and all of them are included in the technical scope of the present invention. In each drawing, for the sake of convenience, hatching, member numbers, etc. may be omitted. In such a case, reference shall be made to the specification and other drawings. Also, the dimensions of various members in the drawings may differ from the actual dimensions because priority is given to facilitating the understanding of the features of the present invention.

[0021] The balloon for a balloon catheter according to an embodiment of the present invention is a balloon for a balloon catheter having an expansion part, a proximal sleeve part located closer to the proximal side than the expansion part, and a distal sleeve part located farther from the distal side than the expansion part, and includes a balloon body having an outer surface and an inner surface, and an outer protruding part protruding radially outward from the outer surface of the balloon body and extending in the longitudinal axis direction of the balloon body. In the contracted state of the balloon, at least one of the following (1) and (2) is satisfied. (1) The radius of a first virtual cylinder C1 having a central axis parallel to the longitudinal axis direction, the bottom surface of which is located at the distal end and the proximal end of the proximal sleeve part, and at least a part of the side surface of which is circumscribed by the proximal sleeve part, is larger than the radius of a virtual circle C0 circumscribed by the expansion part in a radial cross section perpendicular to the longitudinal axis direction at the midpoint in the longitudinal axis direction of the expansion part. (2) The radius of a second virtual cylinder C2 having a central axis parallel to the longitudinal axis direction, the bottom surface of which is located at the distal end and the proximal end of the distal sleeve part, and at least a part of the side surface of which is circumscribed by the distal sleeve part, is larger than the radius of a virtual circle C0 circumscribed by the expansion part in a radial cross section perpendicular to the longitudinal axis direction at the midpoint in the longitudinal axis direction of the expansion part. Thus, in the contracted state of the balloon, since at least one of the radius of the first virtual cylinder C1 circumscribed by the proximal sleeve portion and the radius of the second virtual cylinder C2 circumscribed by the distal sleeve portion is larger than the radius of the virtual circle C0 circumscribed by the expansion portion in the radial cross-section at the midpoint in the longitudinal axis direction of the expansion portion, when transporting the contracted balloon in the body cavity, the expansion portion can be made less likely to contact the body cavity wall by bringing the proximal sleeve portion or the distal sleeve portion into contact with the body cavity wall. Thereby, the contact area of the balloon with the body cavity wall can be reduced, and the trackability of the balloon (the ease of the balloon following the curvature of the body cavity during balloon transportation in the body cavity) can be improved. Also, since the balloon can be transported to the lesion portion with the central portion of the expansion portion being less likely to contact the body cavity wall, the expansion portion that is expanded during treatment and acts on the lesion portion can be protected from damage and effective treatment becomes possible. Furthermore, for example, when a drug is loaded on the expansion portion, loss of the drug can be prevented. In this specification, the balloon for a balloon catheter may be simply referred to as a "balloon".

[0022] With reference to FIGS. 1 to 15, the balloon for a balloon catheter will be described. FIG. 1 shows a side view of a balloon catheter according to an embodiment of the present invention. FIG. 2 shows a longitudinal cross-sectional view of the balloon of the balloon catheter shown in FIG. 1 in an expanded state, and FIG. 3 shows a plan view of the balloon shown in FIG. 2 as viewed from the outer protruding portion side. FIG. 4 shows a cross-sectional view taken along line IV-IV of FIG. 1. FIG. 5 shows a side view of the balloon of the balloon catheter shown in FIG. 1 in a contracted state, and FIG. 6 shows a side view showing another example of the side view shown in FIG. 5. FIG. 7 shows a cross-sectional view taken along line VII-VII of FIG. 5, that is, a radial cross-sectional view at the midpoint in the longitudinal axis direction of the expansion portion. FIGS. 8 to 10 show cross-sectional views showing different examples of the cross-sectional view shown in FIG. 7, that is, cross-sectional views showing examples in which the length of the blade and the number of outer protruding portions are different. FIG. 11 shows a cross-sectional view taken along line XI-XI of FIG. 5, that is, a radial cross-sectional view of the proximal sleeve portion, and FIG. 12 shows a cross-sectional view showing another example of the cross-sectional view shown in FIG. 11. FIG. 13 shows a side view of the balloon for a balloon catheter according to another embodiment of the present invention in a contracted state. FIG. 14 shows a radial cross-sectional view at the midpoint in the longitudinal axis direction of the expansion portion of the balloon of the balloon catheter according to an embodiment of the present invention in a folded state, and FIG. 15 shows a cross-sectional view showing another example of the cross-sectional view shown in FIG. 14, that is, a cross-sectional view showing an example in which the length of the blade is different.

[0023] In the present invention, the proximal side refers to the direction on the side of the user or the operator with respect to the extending direction of the balloon catheter 1 or the longitudinal axis direction x of the shaft 3, and the distal side refers to the direction opposite to the proximal side, that is, the direction on the side of the treatment target. Even for members other than the elongated member such as the shaft 3, they have the same longitudinal axis direction x as the shaft 3. The radial direction y is a direction perpendicular to the longitudinal axis direction x and is a direction connecting the center of the balloon body 27 and a point on the circumscribed circle of the balloon body 27 in the expanded state in a cross-section perpendicular to the longitudinal axis direction x. The circumferential direction z is a direction along the circumference of the circumscribed circle of the balloon body 27 in the expanded state in a cross-section in the radial direction y.

[0024] As shown in FIGS. 1 and 2, the balloon catheter 1 has a shaft 3 and a balloon 2 provided outside the shaft 3. The balloon catheter 1 has a distal side and a proximal side, and the balloon 2 is provided on the distal side of the shaft 3. The balloon catheter 1 is configured such that fluid is supplied into the balloon 2 through the shaft 3, and the inflation and deflation of the balloon 2 can be controlled using an inflator (balloon pressurizer). The fluid may be a pressurized fluid pressurized by a pump or the like.

[0025] The shaft 3 preferably has a fluid flow path inside and further has an insertion passage for a guide wire. In order for the shaft 3 to have a fluid flow path and a guide wire insertion passage inside, for example, the shaft 3 has an outer tube 31 and an inner tube 32, the inner tube 32 functions as an insertion passage for the guide wire, and the space between the inner tube 32 and the outer tube 31 functions as a fluid flow path. In the case where the shaft 3 has the outer tube 31 and the inner tube 32 in this way, it is preferable that the inner tube 32 extends from the distal end of the outer tube 31 and penetrates to the distal side of the balloon 2, the distal side of the balloon 2 is joined to the inner tube 32, and the proximal side of the balloon 2 is joined to the outer tube 31.

[0026] As shown in FIGS. 1 to 12, the balloon 2 for a balloon catheter has an expansion part 20, a proximal side sleeve part 21 located on the proximal side of the expansion part 20, and a distal side sleeve part 22 located on the distal side of the expansion part 20. It has a balloon body 27 having an outer surface and an inner surface, and an outer protruding part 60 protruding outward in the radial direction y from the outer surface of the balloon body 27 and extending in the longitudinal axis direction x of the balloon body 27. In the contracted state of the balloon 2, at least one of the following (1) and (2) is satisfied. (1) A first virtual cylinder C1 having a central axis parallel to the longitudinal axis direction x, with the bottom surface located at the distal end and the proximal end of the proximal sleeve portion 21, and at least a part of the side surface of the proximal sleeve portion 21 circumscribing the first virtual cylinder C1. The radius r1 of the first virtual cylinder C1 is larger than the radius r0 of the virtual circle C0 that circumscribes the expansion portion 20 in the cross-section in the radial direction y perpendicular to the longitudinal axis direction x at the midpoint 20c of the expansion portion 20 in the longitudinal axis direction x. (2) A second virtual cylinder C2 having a central axis parallel to the longitudinal axis direction x, with the bottom surface located at the distal end and the proximal end of the distal sleeve portion 22, and at least a part of the side surface of the distal sleeve portion 22 circumscribing the second virtual cylinder C2. The radius r2 of the second virtual cylinder C2 is larger than the radius r0 of the virtual circle C0 that circumscribes the expansion portion 20 in the cross-section in the radial direction y perpendicular to the longitudinal axis direction x at the midpoint 20c of the expansion portion 20 in the longitudinal axis direction x. In the contracted state of the balloon 2, since at least one of the radius r1 of the first virtual cylinder C1 circumscribed by the proximal sleeve portion 21 and the radius r2 of the second virtual cylinder C2 circumscribed by the distal sleeve portion 22 is larger than the radius r0 of the virtual circle C0 that circumscribes the expansion portion 20 in the cross-section in the radial direction y at the midpoint 20c of the expansion portion 20 in the longitudinal axis direction x, when transporting the contracted balloon 2 in the body cavity, by bringing the proximal sleeve portion 21 or the distal sleeve portion 22 into contact with the body cavity wall, it is possible to make it difficult for the expansion portion 20 to contact the body cavity wall. Thereby, the contact area of the balloon 2 with the body cavity wall can be reduced, and the trackability of the balloon 2 (the ease of the balloon 2 following the curvature of the body cavity during the transportation of the balloon 2 in the body cavity) can be improved. Also, since the balloon 2 can be transported to the lesion portion with the central portion of the expansion portion 20 being difficult to contact the body cavity wall, it is possible to protect the expansion portion 20 that is expanded during treatment and acts on the lesion portion from damage, enabling effective treatment. Furthermore, for example, when a drug is loaded on the expansion portion 20, it is possible to prevent the loss of the drug.

[0027] As shown in FIGS. 1 and 2, the balloon 2 has a proximal sleeve portion 21 and a distal sleeve portion 22 on the proximal side and the distal side of the expansion portion 20, respectively. At least a part of the proximal sleeve portion 21 and the distal sleeve portion 22 can be configured to be fixed to the shaft 3. In the case where the shaft 3 has an outer tube 31 and an inner tube 32, at least a part of the proximal sleeve portion 21 can be fixed to the outer tube 31, and at least a part of the distal sleeve portion 22 can be fixed to the inner tube 32.

[0028] The expansion portion 20 is a portion that is expanded by supplying fluid into the balloon 2 through the shaft 3. It is preferable that the proximal sleeve portion 21 and the distal sleeve portion 22 located on the proximal side or the distal side of the expansion portion 20 do not expand even when fluid is supplied into the balloon 2. Thereby, the fixation between the balloon 2 and the shaft 3 can be stabilized even in the expanded state of the balloon 2. Further, as will be described later, when the balloon 2 is contracted from the expanded state, vanes 29 are formed on the expansion portion 20. However, if the proximal sleeve portion 21 and the distal sleeve portion 22 do not expand, the vanes 29 are not formed on the proximal sleeve portion 21 and the distal sleeve portion 22 even when the balloon 2 is contracted from the expanded state. Thereby, when the balloon 2 is conveyed in the body cavity in the contracted state, the vanes 29 can be configured not to contact the body cavity wall at the proximal sleeve portion 21 and the distal sleeve portion 22.

[0029] Although not shown, the expansion portion 20 may have 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 farther from the distal side than the straight tube portion. The straight tube portion preferably has the same diameter in the longitudinal axis direction x, and the proximal tapered portion and the distal tapered portion are preferably formed so as to reduce the diameter as they move away from the straight tube portion. By having a straight tube portion with the maximum diameter in the expansion portion 20, when the balloon 2 is expanded in a lesion such as a stenosis, the straight tube portion can sufficiently contact the lesion and it becomes easier to expand or incise the lesion. Further, by having the reduced-diameter proximal tapered portion and distal tapered portion, when the balloon 2 is contracted, the outer diameters of the proximal end portion and the distal end portion of the balloon 2 can be reduced to reduce the step between the shaft 3 and the balloon 2, making it easier to insert the balloon 2 into the body cavity.

[0030] As shown in FIGS. 1 to 4, the balloon 2 has a balloon body 27 having an outer surface and an inner surface, and an outer protruding portion 60 that protrudes outward in the radial direction y from the outer surface of the balloon body 27 and extends in the longitudinal axis direction x of the balloon body 27. The maximum length by which the outer protruding portion 60 protrudes outward in the radial direction y from the outer surface of the balloon body 27 in the cross section in the radial direction y is preferably 1.2 times or more, more preferably 1.5 times or more, still more preferably 2 times or more, of the film thickness of the balloon body 27, and it is also allowed to be 100 times or less, 50 times or less, 30 times or less, or 10 times or less. Also, the maximum length may be different in the longitudinal axis direction x. The outer protruding portion 60 having the maximum length within the above range makes it easier to make a cut of an appropriate depth in the stenosis and facilitates the incision. Further, since the balloon 2 has the outer protruding portion 60, it is possible to improve the strength of the balloon 2 and suppress overexpansion of the balloon 2 during pressurization.

[0031] As shown in FIGS. 1 to 8 and FIG. 11, the number of the outer protrusions 60 in the circumferential direction z of the balloon 2 may be plural, or may be one as shown in FIGS. 9, 10, and 12. When the balloon 2 has a plurality of outer protrusions 60 in the circumferential direction z, it is preferable that the plurality of outer protrusions 60 are spaced apart in the circumferential direction z, and more preferably, they are arranged at equal intervals in the circumferential direction z. The separation distance is preferably longer than the maximum circumferential length of the outer protrusion 60. By arranging the outer protrusions 60 spaced apart, preferably at equal intervals, in the circumferential direction z, it becomes easier to fix the balloon 2 and incise the stenosis.

[0032] The outer protrusion 60 extending in the longitudinal axis direction x on the outer surface of the balloon body 27 may be arranged straight in the longitudinal axis direction x at the same position in the circumferential direction z, that is, as shown in FIG. 3. If the outer protrusion 60 is arranged straight, the stenosis can be incised straight. Alternatively, although not shown, the outer protrusion 60 may be arranged spirally so as to go around the outer surface of the balloon body 27 in the circumferential direction z at different positions in the circumferential direction z in the longitudinal axis direction x. With such an outer protrusion, the stenosis can be incised obliquely.

[0033] The balloon 2 preferably satisfies at least one of the following (1) and (2). (1) The outer protrusions 60 of the proximal sleeve portion 21 and the outer protrusions 60 of the expansion portion 20 extend continuously in the longitudinal axis direction x. (2) The outer protrusions 60 of the distal sleeve portion 22 and the outer protrusions 60 of the expansion portion 20 extend continuously in the longitudinal axis direction x. FIG. 3 shows an embodiment satisfying both of the above (1) and (2), that is, an embodiment in which the outer protrusions 60 of the proximal sleeve portion 21, the outer protrusions 60 of the expansion portion 20, and the outer protrusions 60 of the distal sleeve portion 22 extend continuously in the longitudinal axis direction x, but it is sufficient to satisfy at least one of the above (1) and (2). Thereby, it becomes possible to further improve the strength of the balloon 2 and further suppress the overexpansion of the balloon 2 during pressurization.

[0034] Alternatively, although not shown, as long as at least one of the radius r1 of the first virtual cylinder C1 circumscribed by the proximal sleeve portion 21 and the radius r2 of the second virtual cylinder C2 circumscribed by the distal sleeve portion 22 in the contracted state of the balloon 2 satisfies the condition of being larger than the radius r0 of the virtual circle C0 circumscribed by the expansion portion 20 in the cross-section in the radial direction y at the midpoint 20c in the longitudinal axis direction x of the expansion portion 20, the outer protrusions 60 of the proximal sleeve portion 21, the expansion portion 20, and the distal sleeve portion 22 do not have to continuously extend in the longitudinal axis direction x, and there may be a portion where the outer protrusions 60 are not arranged. Thereby, a portion with a small outer diameter of the balloon 2 in the contracted state can be provided, and it becomes possible to reduce the contact area with the body cavity wall of the balloon 2 and improve the trackability.

[0035] As shown in FIG. 4, the outer protrusion 60 has a tip portion 61 in the cross-section in the radial direction y. Since the tip portion 61 makes it easier to make an incision in the stenosis, the stenosis can be incised while preventing the dissociation of the vascular intima. The tip portion 61 is the portion where the outer protrusion 60 protrudes most outward in the radial direction y from the outer surface of the balloon body 27, and may have a shape with an acute angle as shown in FIG. 4, or may have a shape with an obtuse angle, a shape formed by a curve, or a flat shape. From the viewpoint of ease of making an incision, the tip portion 61 preferably has a shape with an acute angle. The shape of the outer protrusion 60 in the cross-section in the radial direction y may be arbitrary, and may be a substantially triangular shape as shown in FIG. 4, or may be a polygon, a sector, a wedge, a convex shape, a spindle shape, or the like.

[0036] As shown in FIGS. 5 and 7, the contracted state of the balloon 2 is the state before fluid is supplied to the inside of the balloon 2 or after the fluid is discharged from the inside of the balloon 2. In the contracted state of the balloon 2, the expansion part 20 has a part where the inner surface of the balloon body 27 is close to the shaft 3 and the blades 29. In the embodiments shown in FIGS. 5 and 7, the shaft 3 has an outer tube 31 and an inner tube 32, and the expansion part 20 has a part where the inner surface of the balloon body 27 is close to the inner tube 32 and the blades 29 in the contracted state of the balloon 2. In the contracted state of the balloon 2, it is preferable that the blades 29 are formed so as to go around the shaft 3 in the circumferential direction z. Before the fluid is supplied to the inside of the balloon 2, particularly in the contracted state of the balloon 2 before use, as shown in FIGS. 7 to 10, the blades 29 go around the shaft 3 in the circumferential direction z, and the balloon membranes are in close contact with each other at the part where there is no outer protrusion 60, and the blades 29 are in close contact with the outer protrusion 60 at the part where the outer protrusion 60 is arranged. It is preferable that the balloon 2 is contracted. Also, even in the contracted state in which the fluid is discharged from the balloon 2 once expanded after use of the balloon 2 or the like, it is preferable that the contracted state has the above-described configuration. Thereby, the radius r0 of the virtual circle C0 circumscribing the expansion part 20 in the cross section in the radial direction y perpendicular to the longitudinal axis direction x at the midpoint 20c in the longitudinal axis direction x of the expansion part 20 can be easily reduced.

[0037] As shown in FIG. 5, the balloon 2 satisfies at least one of the following (1) and (2) in the contracted state. (1) A first virtual cylinder C1 having a central axis parallel to the longitudinal axis direction x, the bottom surface of which is located at the distal end and the proximal end of the proximal sleeve part 21, and the proximal sleeve part 21 circumscribes at least a part of the side surface. The radius r1 of the first virtual cylinder C1 is larger than the radius r0 of the virtual circle C0 circumscribing the expansion part 20 in the cross section in the radial direction y at the midpoint 20c in the longitudinal axis direction x of the expansion part 20. (2) A second virtual cylinder C2 having a central axis parallel to the longitudinal axis direction x, wherein the bottom surface is located at the distal end and the proximal end of the distal sleeve portion 22, and at least a part of the side surface of the second virtual cylinder C2 is circumscribed by the distal sleeve portion 22. The radius r2 of the second virtual cylinder C2 is larger than the radius r0 of the virtual circle C0 circumscribing the expansion portion 20 in the cross-section in the radial direction y at the midpoint 20c of the expansion portion 20 in the longitudinal axis direction x. FIG. 5 shows an embodiment that satisfies both of the above (1) and (2), but it is sufficient to satisfy at least one of the above (1) and (2). When both of the above (1) and (2) are satisfied, the radius r1 of the first virtual cylinder C1 circumscribed by the proximal sleeve portion 21 and the radius r2 of the second virtual cylinder C2 circumscribed by the distal sleeve portion 22 may be the same or either one may be larger. By having the above configuration, when transporting the balloon 2 in the contracted state in the body cavity, by bringing the proximal sleeve portion 21 or the distal sleeve portion 22 into contact with the body cavity wall, it is possible to make it difficult for the expansion portion 20 to contact the body cavity wall. As a result, since the relatively large-area expansion portion 20 is less likely to contact the body cavity wall, the contact area of the balloon 2 with the body cavity wall during transportation can be reduced, and the trackability of the balloon 2 can be improved. Also, since the expansion portion 20 is less likely to contact the body cavity wall, it is possible to protect the expansion portion 20 that is expanded during treatment and acts on the lesion from damage, enabling effective treatment. Furthermore, for example, when a drug is loaded on the expansion portion 20, loss of the drug can be prevented.

[0038] Here, the condition of the above (1) is that it has a central axis parallel to the longitudinal axis direction x, and at least a part of the side surface of the first virtual cylinder C1 having bottom surfaces at the distal end and the proximal end of the proximal sleeve portion 21 is circumscribed by the proximal sleeve portion 21. In other words, when the proximal sleeve portion 21 is housed inside the first virtual cylinder C1 so that the longitudinal axis direction x coincides, at least a part of the side surface of the first virtual cylinder C1 is in contact with the proximal sleeve portion 21. When the proximal sleeve portion 21 has different diameters in the longitudinal axis direction x, the portion having the maximum diameter is in contact with the side surface of the first virtual cylinder C1. The condition of the above (2) for the distal sleeve portion 22 can be understood in the same manner as above.

[0039] When the proximal end of the expansion part 20 is at the 0% position and the distal end is at the 100% position in the longitudinal axis direction x, the midpoint 20c of the expansion part 20 in the longitudinal axis direction x corresponds to the 50% position. However, the radius r1 of the first virtual cylinder C1 circumscribed by the proximal sleeve part 21 and the radius r2 of the second virtual cylinder C2 circumscribed by the distal sleeve part 22 are larger than the radii of the respective virtual circles circumscribed by the expansion part 20 in the cross section in the radial direction y at the 40% position and the 60% position. It is preferable that at least one of them is larger. Further, it is more preferable that at least one of the radius r1 and the radius r2 is larger than the radii of the respective virtual circles circumscribed by the expansion part 20 in the cross section in the radial direction y at the 30% position and the 70% position, and it is even more preferable that at least one of the radius r1 and the radius r2 is larger than the radii of the respective virtual circles circumscribed by the expansion part 20 in the cross section in the radial direction y at the 20% position and the 80% position. Thereby, when transporting the balloon 2 in the contracted state in the body cavity, it is possible to make it more difficult for the expansion part 20 to contact the body cavity wall, and it becomes easier to improve the trackability of the balloon 2 and protect the expansion part 20.

[0040] In the case where the expansion part 20 has a proximal tapered part, a straight tube part, and a distal tapered part, it is preferable that at least one of the radius r1 of the first virtual cylinder C1 circumscribed by the proximal sleeve part 21 and the radius r2 of the second virtual cylinder C2 circumscribed by the distal sleeve part 22 is larger than the radius of the straight tube part. Thereby, when transporting the balloon 2 in the contracted state in the body cavity, it is possible to make it more difficult for the relatively large-area straight tube part to contact the body cavity wall, and it becomes possible to improve the trackability of the balloon 2 and protect the straight tube part.

[0041] It is not necessary for the entire sleeve portion to be circumscribed by each virtual cylinder. For example, as shown in FIG. 6, the distal end portion of the distal sleeve portion 22 may have a portion that does not circumscribe the second virtual cylinder C2. With such a configuration, when the balloon 2 in the contracted state is inserted into the body cavity, the diameter of the tip portion in the advancing direction can be reduced, so that the insertability can be improved. Alternatively, although not shown, the proximal end portion of the proximal sleeve portion 21 may have a portion that does not circumscribe the first virtual cylinder C1. With such a configuration, when the balloon 2 in the contracted state is retracted from the lesion, the diameter of the tip portion in the advancing direction can be reduced, so that the insertability can be improved.

[0042] Referring to FIGS. 7 to 10, in the contracted state of the balloon 2, a virtual circle C0 circumscribing the expansion portion 20 in a cross-section in the radial direction y at the midpoint 20c in the longitudinal axis direction x of the expansion portion 20 will be described. FIGS. 7 and 8 show examples of the virtual circle C0 in the case of the balloon 2 having three outer protrusions 60. As shown in FIG. 7, in an example of the balloon 2 with a relatively large diameter of the expansion portion 20, the length of the blade 29 circulating in the circumferential direction z is relatively long, and in such a case, the blade 29 may circumscribe the virtual circle C0. As shown in FIG. 8, in an example of the balloon 2 with a relatively small diameter of the expansion portion 20, the length of the blade 29 circulating in the circumferential direction z is relatively short, and in such a case, the outer protrusion 60 may circumscribe the virtual circle C0. FIGS. 9 and 10 show examples of the virtual circle C0 in the case of the balloon 2 having one outer protrusion 60. As shown in FIG. 10, in an example of the balloon 2 with a relatively large diameter of the expansion portion 20, the length of the blade 29 circulating in the circumferential direction z is relatively long, and in such a case, the blade 29 may circumscribe the virtual circle C0. As shown in FIG. 9, in an example of the balloon 2 with a relatively small diameter of the expansion portion 20, the length of the blade 29 circulating in the circumferential direction z is relatively short, and in such a case, the outer protrusion 60 and the blade 29 may circumscribe the virtual circle C0. When the outer protrusion 60 circumscribes the virtual circle C0, the tip portion 61 may circumscribe the virtual circle C0. In any case, since at least one of the radius r1 of the first virtual cylinder C1 circumscribing the proximal sleeve portion 21 and the radius r2 of the second virtual cylinder C2 circumscribing the distal sleeve portion 22 is larger than the radius r0 of the virtual circle C0, it is possible to make it difficult for the outer protrusion 60 and the blade 29 of the straight tube portion 20 to contact the body cavity wall.

[0043] Referring to FIGS. 11 and 12, in the contracted state of the balloon 2, in the cross-section in the radial direction y at the midpoint 20c in the longitudinal axis direction x of the expansion part 20, when the radius r1 of the first virtual cylinder C1 circumscribing the proximal sleeve part 21 is larger than the radius r0 of the virtual circle C0 circumscribing the expansion part 20, the first virtual cylinder C1 will be described. FIG. 11 shows an example of the first virtual cylinder C1 in the case of the balloon 2 having three outer protrusions 60, and FIG. 12 shows an example of the first virtual cylinder C1 in the case of the balloon 2 having one outer protrusion 60. FIG. 11 is a cross-sectional view taken along line XI-XI of FIG. 5, and FIG. 5 shows a mode in which the proximal sleeve part 21 circumscribes the first virtual cylinder C1 over the entire longitudinal axis direction x. However, the balloon 2 according to the embodiment of the present invention is not limited to FIG. 5, and it is sufficient if the proximal sleeve part 21 has the cross-section shown in FIG. 11 in a part thereof. Similarly, in the mode shown in FIG. 12, it is sufficient if the balloon 2 has the cross-section shown in FIG. 12 in a part of the proximal sleeve part 21. As shown in FIGS. 11 and 12, in the non-expanded proximal sleeve part 21, the blades 29 are not formed even in the contracted state of the balloon 2, and in the mode shown in FIG. 11, the outer protrusion 60 can circumscribe the first virtual cylinder C1. In other modes including the mode shown in FIG. 12, the outer protrusion 60 and the balloon body 27 may circumscribe the first virtual cylinder C1. The first virtual cylinder C1 can also be regarded as the body cavity wall when the balloon 2 is transported in the body cavity. As shown in FIGS. 11 and 12, the proximal sleeve part 21 contacts the body cavity wall with a small contact area, so that the transport path of the balloon 2 can be ensured, and the trackability of the balloon 2 can be improved.

[0044] As shown in FIG. 12, for example, even when one outer protrusion 60 is provided on the proximal sleeve part 21 and a plurality of outer protrusions 60 are provided on the expansion part 20, the blades 29 of the expansion part 20 cause the balloon membranes to adhere to each other, and the balloon 2 is contracted so as to adhere to the outer protrusion 60 at the portion where the outer protrusion 60 is arranged, whereby at least one of the radii r1 and r2 can be made larger than the radius r0.

[0045] In the contracted state of the balloon 2, for the second virtual cylinder C2 where the radius r2 of the distal sleeve portion 22 is larger than the radius r0 of the virtual circle C0 circumscribing the expansion portion 20 in the cross section in the radial direction y at the midpoint 20c in the longitudinal axis direction x of the expansion portion 20, although not shown in the figure, it can be understood in the same manner by referring to FIGS. 11 and 12 used for the description of the proximal sleeve portion 21 above.

[0046] From the viewpoint of protecting the expansion portion 20, as shown in FIGS. 5 and 6, in the contracted state of the balloon 2, both the radius r1 of the first virtual cylinder C1 circumscribing the proximal sleeve portion 21 and the radius r2 of the second virtual cylinder C2 circumscribing the distal sleeve portion 22 are larger than the radius r0 of the virtual circle C0 circumscribing the expansion portion 20 in the cross section in the radial direction y at the midpoint 20c in the longitudinal axis direction x of the expansion portion 20. From the viewpoint of ease of insertion during conveyance of the balloon 2, it is preferable that either the radius r1 of the first virtual cylinder C1 circumscribing the proximal sleeve portion 21 or the radius r2 of the second virtual cylinder C2 circumscribing the distal sleeve portion 22 is larger than the radius r0 of the virtual circle C0 circumscribing the expansion portion 20 in the cross section in the radial direction y at the midpoint 20c in the longitudinal axis direction x of the expansion portion 20. In particular, when only the radius r1 of the first virtual cylinder C1 circumscribing the proximal sleeve portion 21 is larger than the radius r0, the outer diameter of the distal sleeve portion 22 on the distal end side when inserting into the body cavity can be suppressed, and the conveyance of the balloon 2 in the body cavity can be facilitated. Also, since the radius r1 is larger than the radius r0, when conveying the balloon 2 in the body cavity, by bringing the proximal sleeve portion 21 into contact with the body cavity wall and supporting the body cavity wall on the proximal side of the balloon 2, it is possible to make it difficult to bring the expansion portion 20 into contact with the body cavity wall while securing the conveyance path of the balloon 2, and it is possible to improve the trackability of the balloon 2 and protect the expansion portion 20. When the radius r2 of the distal sleeve portion 22 is larger than the radius r0, when conveying the balloon 2, the distal sleeve portion 22 comes into contact with the body cavity wall and the conveyance path of the balloon 2 can be secured, so there is an advantage that it is possible to prevent deterioration of the insertability of the balloon 2 due to the contraction state of the balloon 2 being disturbed such as the tip of the balloon film being rolled up when the expansion portion 20 comes into contact with the body cavity wall.

[0047] The radius r0, the radius r1, and the radius r2 can be adjusted by changing the radial length in the y-direction of the outer protrusion 60 in the cross-section in the radial direction y in the expansion part 20, the proximal sleeve part 21, and the distal sleeve part 22. However, depending on how the expansion part 20 is contracted, the radius r0 can be adjusted regardless of the radial length in the y-direction of the outer protrusion 60. As a result, the relationship between the radius r0, the radius r1, and the radius r2 can be adjusted. That is, when the balloon 2 is contracted, the balloon membranes are in close contact with each other at the part without the outer protrusion 60, and the balloon 2 is contracted so that the blade 29 is in close contact with the outer protrusion 60 at the part where the outer protrusion 60 is arranged, whereby the radius r0 can be made smaller than at least one of the radius r1 and the radius r2. With this method, the radius r0 can be adjusted regardless of the radial length in the y-direction of the outer protrusion 60 in the cross-section in the radial direction y in the expansion part 20, the proximal sleeve part 21, and the distal sleeve part 22. As a result, the relationship between the radius r0, the radius r1, and the radius r2 can be adjusted.

[0048] As shown in FIG. 13, the expansion part 20 has a main section 20m excluding 10% each from the distal end and the proximal end in the longitudinal axis direction x. In the contracted state of the balloon 2, it is preferable that at least one of the following (1) and (2) is satisfied. (1) The radius r1 of the first virtual cylinder C1 is larger than the radius r3 of the third virtual cylinder C3 having a central axis parallel to the longitudinal axis direction x, with the bottom surface located at the distal end and the proximal end of the main section 20m and at least a part of the side surface circumscribing the main section 20m. (2) The radius r2 of the second virtual cylinder C2 is larger than the radius r3 of the third virtual cylinder C3 having a central axis parallel to the longitudinal axis direction x, with the bottom surface located at the distal end and the proximal end of the main section 20m and at least a part of the side surface circumscribing the main section 20m. In the contracted state of the balloon 2, at least one of the radius r1 of the first virtual cylinder C1 circumscribed by the proximal sleeve portion 21 and the radius r2 of the second virtual cylinder C2 circumscribed by the distal sleeve portion 22 is larger than the radius r3 of the third virtual cylinder C3 circumscribed by the main section 20m of the expansion portion 20. Therefore, when transporting the contracted balloon 2 within the body cavity, it is possible to make it difficult for the entire main section 20m of the expansion portion 20 to contact the body cavity wall. As a result, the contact area of the balloon 2 with the body cavity wall can be further reduced, and the trackability of the balloon 2 can be further improved. Also, since the balloon 2 can be transported to the lesion site such that it is difficult for the entire main section 20m of the expansion portion 20 to contact the body cavity wall, it is possible to protect the main section 20m, which is expanded during treatment and acts on the lesion site, from damage, or to prevent loss of the drug, for example, when the main section 20m is loaded with a drug.

[0049] The main section 20m is a section that is 10% each in the longitudinal axis direction x from the distal end and the proximal end of the expansion portion 20, that is, a section excluding the portion with the smallest diameter in the expanded state of the expansion portion 20. In other words, the main section 20m is a section having a diameter of a certain size or more in the expanded state. As a result, in the contracted state of the balloon 2, vanes 29 having a length of a certain size or more that circulate in the circumferential direction z are formed in the main section 20m, and by contracting the balloon 2 such that the vanes 29 are in close contact with the outer protrusion 60, the radius r0 can be made smaller than at least one of the radius r1 and the radius r2.

[0050] In the above aspect, the radius r3 of the third virtual cylinder C3 circumscribed by the main section 20m of the extension portion 20 may be larger than, equal to, or smaller than the radius r0 of the virtual circle C0 circumscribed by the extension portion 20 in the cross-section in the radial direction y perpendicular to the longitudinal axis direction x at the midpoint 20c in the longitudinal axis direction x of the extension portion 20. In view of the fact that at least one of the radius r1 of the first virtual cylinder C1 circumscribed by the proximal sleeve portion 21 and the radius r2 of the second virtual cylinder C2 circumscribed by the distal sleeve portion 22 is larger than the radius r0, it is preferable that the radius r3 of the third virtual cylinder C3 circumscribed by the main section 20m is larger than the radius r0. Thereby, in the contracted state, the diameter of the central portion of the extension portion 20 can be further suppressed with respect to the proximal end portion or the distal end portion of the balloon 2, which is preferable from the viewpoints of improving the trackability and protecting the extension portion 20.

[0051] In the contracted state of the balloon 2, it is preferable that the balloon 2 is folded. By folding the balloon 2 in the contracted state before supplying fluid into the balloon 2 or after the fluid is discharged from the inside of the balloon 2 using hands, various folding machines, etc., the balloon 2 in the folded state can be obtained. In the folded state, the blades 29 are folded so as to firmly go around the shaft 3 and do not float from the shaft 3, so that it is possible to prevent the blades 29 from contacting the body cavity wall during transportation. Thereby, since the radius r0 can be easily reduced, the extension portion 20 can be made less likely to contact the body cavity wall, and the trackability of the balloon 2 can be further improved. Further, since the extension portion 20 is less likely to contact the body cavity wall, it is possible to better protect the extension portion 20 that is expanded during treatment and acts on the lesion portion from damage.

[0052] For example, as shown in FIGS. 14 and 15, in the folded state of the balloon 2, the blades 29 may be firmly folded, and the outer protrusion 60 may be deformed in the circumferential direction z of the blades 20. By folding in this way, the radius r0 can be more easily reduced. As a method of folding the balloon 2 in this way, there is an example of shaping the balloon 2 using hands or various folding machines. By folding the balloon 2 in this way, the radius r0 can be adjusted regardless of the length in the radial direction y of the outer protrusion 60, and as a result, the relationship between the radius r0, the radius r1, and the radius r2 can be adjusted. That is, the radius r0 can be reduced by deforming the outer protrusion 60 in the circumferential direction z of the blade 29, and the radius r0 can be made smaller than at least one of the radius r1 and the radius r2.

[0053] In addition, since the main section 20m has blades 29 having a length equal to or greater than a certain length that circulates in the circumferential direction z, if the outer protrusion 60 is folded so as to be deformed in the circumferential direction z of the blade 29 over the entire main section 20m of the expansion section 20, the radius r3 of the third virtual cylinder C3 circumscribed by the main section 20m can be easily reduced, and the radius r3 can be made smaller than at least one of the radius r1 and the radius r2. Thereby, it is possible to make it difficult for the entire main section 20m to contact the body cavity wall, and it is possible to further reduce the contact area of the balloon 2 with the body cavity wall.

[0054] The outer protrusion 60 has a tip 61 in the cross section in the radial direction y, and preferably satisfies at least one of the following (1) and (2) in the contracted state of the balloon 2. (1) In the proximal sleeve portion 21, the tip 61 circumscribes at least a part of the side surface of the first virtual cylinder C1. (2) In the distal sleeve portion 22, the tip 61 circumscribes at least a part of the side surface of the second virtual cylinder C2. Since the distal end portion 61 is circumscribed about the virtual cylinder, the area of the sleeve portion circumscribed about the virtual cylinder can be reduced. The virtual cylinder can also be regarded as the body cavity wall when the balloon 2 is transported in the body cavity. By having the sleeve portion contact the body cavity wall with a small contact area, the transport path of the balloon 2 can be ensured and the trackability of the balloon 2 can be improved. In this case, as shown in FIG. 11, only the distal end portion 61 may be circumscribed about the virtual cylinder, or as shown in FIG. 12, both the distal end portion 61 and the balloon body 27 may be circumscribed about the virtual cylinder. Alternatively, although not shown, the distal end portion 61 and other parts, for example, locations other than the distal end portion 61 of the outer protruding portion 60, may be circumscribed. FIGS. 11 and 12 show the proximal sleeve portion 21 circumscribed about the first virtual cylinder C1, and the distal sleeve portion 22 circumscribed about the second virtual cylinder C2 can be similarly understood with reference to FIGS. 11 and 12.

[0055] The outer protruding portion 60 has a distal end portion 61 in the cross-section in the radial direction y, and preferably satisfies at least one of the following (1) and (2) in the contracted state of the balloon 2. (1) In the proximal sleeve portion 21, only the distal end portion 61 is circumscribed about at least a part of the side surface of the first virtual cylinder C1. (2) In the distal sleeve portion 22, only the distal end portion 61 is circumscribed about at least a part of the side surface of the second virtual cylinder C2. Since only the distal end portion 61 is circumscribed about the virtual cylinder, the area of the sleeve portion circumscribed about the virtual cylinder can be made even smaller. The virtual cylinder can also be regarded as the body cavity wall when the balloon 2 is transported in the body cavity. By having the sleeve portion contact the body cavity wall with an even smaller contact area, the transport path of the balloon 2 can be ensured and the trackability of the balloon 2 can be further improved. In this case, the sleeve portion can be configured such that, for example, as shown in FIG. 11, a plurality of outer protruding portions 60 are arranged at intervals in the circumferential direction z. FIG. 11 shows the proximal sleeve portion 21 circumscribed about the first virtual cylinder C1, and the distal sleeve portion 22 circumscribed about the second virtual cylinder C2 can be similarly understood with reference to FIG. 11.

[0056] In the contracted state of the balloon 2, it is preferable that the expansion part 20 has vanes 29 and the vanes 29 are circumscribed about the virtual circle C0. As can be seen from a comparison between FIGS. 7 and 8 or FIGS. 9 and 10, by adjusting the diameter of the balloon body 27, the length by which the vanes 29 revolve in the circumferential direction z can be adjusted, but by making the vanes 29 have a length of a certain value or more, a configuration can be adopted in which the vanes 29 are circumscribed about the virtual circle C0. For example, in a configuration in which the vanes 29 are circumscribed about the virtual circle C0 as shown in FIGS. 7 and 10, it is easy to protect the outer protrusion 60 from damage, and even if the expansion part 20 happens to contact the body cavity wall when the balloon 2 is being transported within the body cavity, since it is difficult for the outer protrusion 60 that acts on the lesion part to contact the body cavity wall, it is possible to prevent the outer protrusion 60 from acting on the body cavity wall at an unintended location.

[0057] In FIGS. 7 to 10, an aspect in which there are three vanes 29 is shown, but as long as the balloon 2 can be contracted, the number of vanes 29 is not particularly limited. For example, two or more are preferable, three or more are more preferable, and four or more or five or more may be acceptable. Also, for the vanes 29, for example, ten or less is preferable, eight or less is more preferable, and six or less is even more preferable. If the number of vanes 29 is within the above range, the balloon 2 can be easily contracted.

[0058] In the contracted state of the balloon 2, it is preferable that the expansion part 20 has vanes 29 and the outer protrusion 60 is arranged other than the vanes 29. If the outer protrusion 60 is arranged other than the vanes 29, since the outer protrusion 60 does not obstruct the revolution of the vanes 29, the balloon 2 can be easily contracted. Also, by arranging the outer protrusion 60 other than the vanes 29, the outer protrusion 60 can be easily covered by the vanes 29 in the contracted state of the balloon 2. Thereby, it becomes easy to adopt a configuration in which the vanes 29 are circumscribed about the virtual circle C0 in the contracted state of the balloon 2.

[0059] Next, with reference to FIGS. 16 to 18, a balloon for a balloon catheter according to another embodiment of the present invention will be described. FIG. 16 shows a side view of the balloon for a balloon catheter according to still another embodiment of the present invention in a contracted state. FIG. 17 shows a cross-sectional view taken along line XVII-XVII of FIG. 16, that is, a radial cross-sectional view of the distal sleeve portion, and FIG. 18 shows a cross-sectional view representing another example of the cross-sectional view shown in FIG. 17.

[0060] As shown in FIG. 16, in the contracted state of the balloon 2, the radius r1 of the first virtual cylinder C1 in the proximal sleeve portion 21 is preferably larger than the radius r0 of the virtual circle C0 in the expansion portion 20, and the radius r2 of the second virtual cylinder C2 in the distal sleeve portion 22 is preferably smaller than the radius r0 of the virtual circle C0. By adopting such a configuration, the outer diameter of the distal sleeve portion 22, which is the tip side when inserted into the body cavity, can be suppressed, and the conveyance of the balloon 2 within the body cavity can be facilitated. Further, since the radius r1 is larger than the radius r0, when the balloon 2 is conveyed within the body cavity, the proximal sleeve portion 21 is brought into contact with the body cavity wall to support the body cavity wall on the proximal side of the balloon 2, thereby making it difficult to bring the expansion portion 20 into contact with the body cavity wall while securing the conveyance path of the balloon 2, and improving the trackability of the balloon 2 and protecting the expansion portion 20 can be realized. Thus, by adopting the above configuration, the balloon 2 can be easily inserted, and at the same time, the trackability can be improved and the expansion portion 20 can be easily protected.

[0061] As shown in FIG. 17, the above configuration may be formed by shortening the length in the radial direction y of the outer protruding portion 60 in the cross-section in the radial direction y of the distal sleeve portion 22, or may be formed by not providing the outer protruding portion 60 on the distal sleeve portion 22. By shortening the length in the radial direction y of the outer protruding portion 60 or not providing the outer protruding portion 60, the radius r2 of the second virtual cylinder C2 circumscribed by the distal sleeve portion 22 can be reduced.

[0062] Alternatively, in order to reduce the radius r2, as shown in FIG. 18, it is preferable that the distal sleeve portion 22 has an inner protruding portion 70 that protrudes inward in the radial direction y from the inner surface of the balloon body 27 and extends in the longitudinal axis direction x. At this time, as shown in FIG. 18, an outer protruding portion 60 having a short length in the radial direction y in the cross-section in the radial direction y may be provided, or the outer protruding portion 60 may not be provided although not shown. By providing the inner protruding portion 70, it is possible to improve the strength of the balloon 2 and suppress over-expansion of the balloon 2 during pressurization even when the length of the outer protruding portion 60 in the radial direction y is short or the outer protruding portion 60 is not provided. When the outer protruding portion 60 is also provided together with the inner protruding portion 70, it is preferable that the inner protruding portion 70 and the outer protruding portion 60 are provided at the same position in the circumferential direction z. This makes it easier to improve the strength of the balloon 2 and suppress over-expansion of the balloon 2 during pressurization.

[0063] As shown in FIG. 16, the expansion portion 20 has a main section 20m excluding 10% each from the distal end and the proximal end in the longitudinal axis direction x. In the contracted state of the balloon 2, the radius r1 of the first virtual cylinder C1 in the proximal sleeve portion 21 is a third virtual cylinder C3 having a central axis parallel to the longitudinal axis direction x, and the bottom surface is located at the distal end and the proximal end of the main section 20m, and at least a part of the side surface has a radius r3 of the third virtual cylinder C3 that circumscribes the main section 20m. It is preferable that the radius r2 of the second virtual cylinder C2 in the distal sleeve portion 22 is smaller than the radius r3 of the third virtual cylinder C3. With such a configuration, when transporting the contracted balloon 2 in the body cavity, it is possible to make it difficult for the entire main section 20m of the expansion portion 20 to contact the body cavity wall. In addition, the outer diameter of the distal sleeve portion 22, which is the tip side when inserted into the body cavity, can be suppressed, and the transportation of the balloon 2 in the body cavity can be facilitated. Since the radius r1 is larger than the radius r3, when transporting the balloon 2 in the body cavity, the proximal sleeve portion 21 is brought into contact with the body cavity wall to support the body cavity wall on the proximal side of the balloon 2, thereby securing the transport path of the balloon 2 while making it difficult for the entire main section 20m of the expansion portion 20 to contact the body cavity wall. It is possible to obtain a balloon 2 that can be easily inserted, has better trackability, and is easier to protect the expansion portion 20.

[0064] Examples of the material constituting the balloon body 27 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 resins, silicone resins, and natural rubbers such as latex rubber. These may be used alone or in combination of two or more. Among them, polyamide resins, polyester resins, and polyurethane resins are preferably used. In particular, it is preferable to use an elastomer resin from the viewpoints of thinning the balloon body 27 and flexibility. For example, among polyamide resins, nylon 12, nylon 11, etc. are suitable as the resin constituting the balloon body 27, and nylon 12 is more suitable because it can be formed relatively easily during blow molding. Also, from the viewpoints of thinning the balloon body 27 and flexibility, polyamide elastomers such as polyether ester amide elastomer and polyamide ether elastomer are preferably used. Among them, polyether ester amide elastomer is preferably used because of its high yield strength and good dimensional stability of the balloon body 27.

[0065] The outer protrusion 60 is preferably made of the same material as the balloon body 27. If the outer protrusion 60 is made of the same material as the balloon body 27, it is possible to prevent the outer protrusion 60 from easily scratching the outer surface of the balloon body 27 while maintaining the flexibility of the balloon 2. The balloon body 27 and the outer protrusion 60 are preferably integrally formed. Thereby, it is possible to prevent the outer protrusion 60 from falling off the balloon body 27. In the mode where the inner protrusion 70 is formed, the inner protrusion 70 is also preferably made of the same material as the balloon body 27 for the same reason as above.

[0066] The balloon 2 can be manufactured by disposing a tubular parison 200 made of resin, as shown in FIG. 19 for example, in a mold having grooves in its inner cavity and performing biaxial stretch blow molding. The outer protrusion 60 can be formed, for example, by inserting the parison 200 into the inner cavity of the mold, causing the thick portion 220 of the parison 200 to enter the grooves of the mold, and introducing a fluid into the inner cavity 210 of the parison 200 to expand the parison 200. The radial length in the radial direction y of the outer protrusion 60 in the cross-section in the radial direction y can be adjusted by the thickness of the thick portion 220 of the parison 200 and the depth of the grooves of the mold. Further, the inner protrusion 70 can be formed, for example, by pressing the thick portion 220 of the parison 200 against a portion of the mold without grooves and introducing a fluid into the inner cavity 210 of the parison 200 to expand the parison 200. Furthermore, to form the outer protrusion 60 and the inner protrusion 70 having a short radial length in the radial direction y in the cross-section in the radial direction y, for example, the thick portion 220 of the parison 200 can be pressed against a portion of the mold with shallow grooves, and a fluid can be introduced into the inner cavity 210 of the parison 200 to expand the parison 200. As the material constituting the parison 200, reference can be made to the description of the material constituting the balloon body 27 above.

[0067] Examples of the material constituting the shaft 3 include polyamide-based resins, polyester-based resins, polyurethane-based resins, polyolefin-based resins, fluorine-based resins, vinyl chloride-based resins, silicone-based resins, natural rubbers, and the like. These may be used alone or in combination of two or more. Among them, the material constituting the shaft 3 is preferably at least one of a polyamide-based resin, a polyolefin-based resin, and a fluorine-based resin. Thereby, the slipperiness of the surface of the shaft 3 can be enhanced, and the insertability of the balloon catheter 1 in the body cavity can be improved.

[0068] The joining of the balloon 2 and the shaft 3 includes adhesion with an adhesive, welding, attaching a ring-shaped member to the overlapping portion of the end of the balloon 2 and the shaft 3 and caulking, etc. Among these, it is preferable that the balloon 2 and the shaft 3 are joined by welding. Since the balloon 2 and the shaft 3 are welded, even if the balloon 2 is repeatedly expanded and contracted, the joining of the balloon 2 and the shaft 3 is difficult to be released, and the joining strength between the balloon 2 and the shaft 3 can be easily increased.

[0069] As shown in FIG. 1, in the balloon catheter 1, a hub 4 may be provided on the proximal side of the shaft 3, and the hub 4 may be provided with a fluid injection portion 7 communicating with the flow path of the fluid supplied into the balloon 2. Further, the hub 4 preferably has a guide wire insertion portion 5 communicating with the insertion path of the guide wire. Since the balloon catheter 1 has the hub 4 including the fluid injection portion 7 and the guide wire insertion portion 5, operations such as supplying fluid into the balloon 2 to expand and contract the balloon 2 and delivering the balloon catheter 1 along the guide wire to the treatment site can be easily performed. The balloon 2 according to the embodiment of the present invention can be applied not only to a so-called over-the-wire type balloon catheter in which the guide wire is inserted from the distal side to the proximal side of the shaft 3 as shown in FIG. 1, but also to a so-called rapid exchange type balloon catheter in which the guide wire is inserted up to the middle of the shaft from the distal side to the proximal side.

[0070] The joining of the shaft 3 and the hub 4 includes, for example, adhesion with an adhesive, welding, etc. Among these, it is preferable that the shaft 3 and the hub 4 are joined by adhesion. Since the shaft 3 and the hub 4 are adhered, for example, when the material constituting the shaft 3 is different from the material constituting the hub 4, such as the shaft 3 being made of a highly flexible material and the hub 4 being made of a highly rigid material, the joining strength between the shaft 3 and the hub 4 can be increased to improve the durability of the balloon catheter 1.

[0071] This application claims the benefit of priority based on Japanese Patent Application No. 2021-8307 filed on January 21, 2021. The entire contents of the specification of Japanese Patent Application No. 2021-8307 filed on January 21, 2021 are incorporated herein by reference.

Explanation of Reference Numerals

[0072] 1: Balloon catheter 2: Balloon 3: Shaft 4: Hub 5: Guide wire insertion portion 7: Fluid injection portion 20: Expansion portion 20c: Midpoint in the longitudinal axis direction of the expansion portion 20m: Main section of the expansion portion 21: Proximal sleeve portion 22: Distal sleeve portion 27: Balloon body 29: Fin 31: Outer tube 32: Inner tube 60: Outer protrusion 61: Tip 70: Inner protrusion 200: Parison 210: Lumen of the parison 220: Wall thickness portion of the parison C0: Virtual circle circumscribed by the expansion portion at the midpoint in the longitudinal axis direction C1: First virtual cylinder circumscribed by the proximal sleeve portion C2: Second virtual cylinder circumscribed by the distal sleeve portion C3: Third virtual cylinder circumscribed by the main section of the expansion portion r0: Radius of the virtual circle C0 r1: Radius of the first virtual cylinder C1 r2: Radius of the second virtual cylinder C2 r3: Radius of the third virtual cylinder C3 x: Longitudinal axis direction y: Radial direction z: Circumferential direction

Claims

1. A balloon for a balloon catheter having an expansion portion, a proximal sleeve portion located proximal to the expansion portion, and a distal sleeve portion located distal to the expansion portion, a balloon body having an outer surface and an inner surface, and an outer protruding portion protruding radially outward from the outer surface of the balloon body and extending in the longitudinal axis direction of the balloon body, the expansion portion having a main section excluding 10% each from the distal end and the proximal end in the longitudinal axis direction, in the contracted state of the balloon, vanes are formed throughout the main section, and the vanes are not formed throughout the proximal sleeve portion and the distal sleeve portion, a balloon for a balloon catheter satisfying at least one of the following (1) and (2) in the contracted state of the balloon. (1) A first virtual cylinder C having a central axis parallel to the longitudinal axis １ wherein the first bottom surface and the second bottom surface are respectively located at the distal end and the proximal end of the proximal sleeve portion, and the proximal sleeve portion is circumscribed by at least a part of the side surface of the first virtual cylinder C １ The radius of is larger than the radius of a virtual circle C circumscribed by the expansion portion in a radial cross-section perpendicular to the longitudinal axis at the midpoint of the expansion portion in the longitudinal axis direction ０ and is larger than the radius of a third virtual cylinder C3 having a central axis parallel to the longitudinal axis, wherein the first bottom surface and the second bottom surface are respectively located at the distal end and the proximal end of the main section, and at least a part of the side surface of the third virtual cylinder C3 circumscribes the main section. (2) A second virtual cylinder C having a central axis parallel to the longitudinal axis ２ wherein the first bottom surface and the second bottom surface are respectively located at the distal end and the proximal end of the distal sleeve portion, and the distal sleeve portion circumscribes at least a part of the side surface of the second virtual cylinder C ２ The radius of is larger than the radius of the virtual circle C circumscribing the expansion portion in the radial cross-section perpendicular to the longitudinal axis at the midpoint of the expansion portion in the longitudinal axis direction ０ and is larger than the radius of a third virtual cylinder C3 having a central axis parallel to the longitudinal axis, wherein the first bottom surface and the second bottom surface are respectively located at the distal end and the proximal end of the main section, and the main section circumscribes at least a part of the side surface of the third virtual cylinder C3.

2. The balloon for a balloon catheter according to claim 1, wherein the balloon is folded in the contracted state of the balloon.

3. The outer protruding portion has a tip portion in the radial cross section, and the balloon for a balloon catheter according to claim 1 or 2 satisfying at least one of the following (1) and (2) in the contracted state of the balloon. (1) In the proximal sleeve portion, the tip portion is circumscribed about at least a part of the side surface of the first virtual cylinder C １ of the side surface of the first virtual cylinder C (2) In the distal sleeve portion, the tip portion circumscribes at least a part of the side surface of the second virtual cylinder C ２ .

4. The outer protruding portion has a tip portion in the radial cross section, and the balloon for a balloon catheter according to any one of claims 1 to 3 satisfying at least one of the following (1) and (2) in the contracted state of the balloon. (1) In the proximal sleeve portion, only the tip portion is circumscribed by at least a part of the side surface of the first virtual cylinder C. １ ​ (2) In the distal sleeve portion, only the tip portion is circumscribed about at least a part of the side surface of the second virtual cylinder C. ２ ​

5. In the contracted state of the balloon, the expansion part has blades, and the blades are tangent to the virtual circle C ０ The balloon for a balloon catheter according to any one of claims 1 to 4, wherein the balloon is circumscribed to the virtual circle C

6. The balloon for a balloon catheter according to any one of claims 1 to 5, wherein the expansion portion has vanes and the outer protruding portion is arranged other than the vanes in the contracted state of the balloon.

7. The balloon for a balloon catheter according to any one of claims 1 to 6 satisfying at least one of the following (1) and (2). (1) The outer protruding portions of the proximal sleeve portion and the expansion portion are continuously extended in the longitudinal axis direction. (2) The outer protruding portions of the distal sleeve portion and the expansion portion are continuously extended in the longitudinal axis direction.

8. In the contracted state of the balloon, the radius of the first virtual cylinder C in the proximal sleeve portion １ is larger than the radius of the virtual circle C in the expansion portion ０ , and the radius of the second virtual cylinder C in the distal sleeve portion ２ is smaller than the radius of the virtual circle C ０ . The balloon for a balloon catheter according to any one of claims 1 to 7

9. In the contracted state of the balloon, the radius of the first virtual cylinder C in the proximal sleeve portion １ is larger than the radius of the third virtual cylinder C ３ , and the radius of the second virtual cylinder C in the distal sleeve portion ２ is smaller than the radius of the third virtual cylinder C ３ . The balloon for a balloon catheter according to claim 8.

10. The balloon for a balloon catheter according to claim 8 or 9, wherein in the distal sleeve portion, there is an inner protruding portion that protrudes radially inward from the inner surface of the balloon body and extends in the longitudinal axis direction.

11. The balloon for a balloon catheter according to any one of claims 1 to 10, wherein the outer protruding portion is made of the same material as the balloon body.

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