Balloon for balloon catheter

Abstract

Provided is a balloon for a balloon catheter that prevents kinking, buckling, and elongation in the long axis direction of the balloon, and that is easy to handle. A balloon for a balloon catheter (2) has a balloon main body (20) that has an expansion portion (20e), a distal side sleeve portion (25) having a fixed portion (25f) fixed to a shaft (3), and a proximal side sleeve portion (21), and has a reinforcing portion (60) on a portion of the inner surface of the distal side sleeve portion (25) on the proximal side of the distal end of the fixed portion (25f) and in the circumferential direction of the distal side sleeve portion (25), and does not have a reinforcing portion (60) on the inner surface of the proximal side sleeve portion (21).

Description

TECHNICAL FIELD

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

[0002] As one of treatments of angina pectoris, myocardial infarction and the like caused by stenosis of a blood vessel, there is angioplasty in which a balloon catheter is used to expand the stenosis. In addition, in addition to blood vessels, various balloon catheters have been proposed for the purpose of expanding stenosis of a body lumen such as a trachea, a digestive tract and the like. The treatment using a balloon catheter is a minimally invasive therapy that does not require a thoracotomy like a bypass surgery, and is therefore widely performed.

[0003] A balloon catheter is also inserted from a site apart from a lesion to be treated, and for example, in the case where the balloon catheter is delivered to a heart, the balloon catheter is mainly inserted from an artery of a femoral artery or a wrist, an upper arm. Therefore, in order to perform a safe treatment, it is required that the balloon catheter easily travels to a desired direction while following a body lumen which is thin and curved from an insertion site to a lesion. For example, a balloon catheter is disclosed in Patent Literature 1 in which a balloon is formed to have a multilayer structure of a base material layer and a coating layer which is softer than the base material layer, so as to impart strength and softness and improve tracking ability (a property that the balloon can advance while following a winding blood vessel). In addition, a balloon catheter is disclosed in Patent Literature 2 in which a tip tip is formed to have a tapered shape in which a tip portion is tapered and a wall thickness of the tip tapered portion is continuously thinned, for the purpose of softening and reducing the diameter of the tip tip. A balloon catheter is disclosed in Patent Literature 3 in which a tip tip is formed of a soft resin.

[0004] Patent Literature 1: Japanese Patent Application Laid-Open No. 2005-246097

[0005] Patent Literature 2: Japanese Patent Application Laid-Open No. 2008-264569

[0006] Patent Literature 3: International Publication No. 2017 / 158735

[0007] In order to safely perform a desired treatment using a balloon catheter, it is required that the balloon catheter is easily delivered to a desired treatment site while following a body lumen according to an operation of an operator. However, the above-described balloon, although it can improve tracking ability to some extent by having a certain strength and softness, has room for improvement in terms of kinking of the balloon when the balloon is bent, crimping of the balloon when the balloon is crushed in an axial direction, and prevention of elongation of the balloon in a longitudinal direction. Therefore, an object of the present application is to provide a balloon for a balloon catheter which can prevent kinking of the balloon, crimping of the balloon, and elongation of the balloon in a longitudinal direction, and which can be easily operated. SUMMARY

[0008] An embodiment of the balloon catheter balloon of the present invention, which can achieve the above-mentioned problem, has the following features: it has a balloon body having an expansion portion, a distal cannula portion located distal to the expansion portion, and a proximal cannula portion located closer to the position of the expansion portion. The distal cannula portion has a fixing portion fixed to the axis. A reinforcing portion is provided on a portion of the inner surface of the distal cannula portion closer to the position of the fixing portion and in the circumferential direction. The inner surface of the proximal cannula portion does not have the reinforcing portion.

[0009] In the balloon catheter described above, the dilation portion preferably has a straight tube portion and a distal conical portion located distal to the straight tube portion. When the distal end of the distal conical portion is set to 0% in the long axis direction of the dilation portion and the proximal end of the distal conical portion is set to 100%, a reinforcing portion is provided on the inner surface of the distal conical portion and in a portion of the circumferential direction of the distal conical portion in the interval from 0% to 10% of the distal conical portion.

[0010] In the above-mentioned balloon catheter, it is preferable that the reinforcing portion of the distal cannula and the reinforcing portion of the distal tapered portion extend continuously in the long axis direction of the balloon body.

[0011] In the balloon of the above-mentioned balloon catheter, the reinforcing part is preferably made of resin.

[0012] In the balloon of the above-mentioned balloon catheter, the reinforcing part is preferably made of metal.

[0013] The balloon used in the aforementioned balloon catheter prevents bending, twisting, and compression along the long axis of the balloon during catheter manipulation, such as delivery and treatment. It also prevents elongation along the long axis of the balloon when inflated by introducing pressurized fluid. Furthermore, when the balloon expands or contracts by introducing or removing fluid, the balloon's inflation and deflation times are minimized, thus avoiding treatment delays. Attached Figure Description

[0014] Figure 1 A side view of a balloon catheter according to one embodiment of the present invention is shown.

[0015] Figure 2 Show Figure 1 A cross-sectional view along the long axis of the distal portion of the balloon catheter shown.

[0016] Figure 3 A cross-sectional view along the long axis of the distal portion of a balloon catheter according to another embodiment of the present invention is shown.

[0017] Figure 4A cross-sectional view along the long axis of the distal portion of a balloon catheter according to another embodiment of the present invention is shown.

[0018] Figure 5 Show Figure 1 VV sectional view.

[0019] Figure 6 Showing the representation Figure 5 A cross-sectional view of a modified example.

[0020] Figure 7 Show Figure 1 Sectional view VII-VII.

[0021] Figure 8 A cross-sectional view along the long axis of a balloon catheter according to another embodiment of the present invention is shown. Detailed Implementation

[0022] The present invention will now be specifically described based on embodiments, but the present invention is of course not limited to the following embodiments, and may be implemented by appropriate modifications within the scope that can conform to the foregoing and following spirit, all of which are included within the technical scope of the present invention. Furthermore, in the various drawings, for convenience, shaded lines, component reference numerals, etc., are sometimes omitted; in such cases, refer to the specification and other drawings. Additionally, the dimensions of various components in the drawings are primarily helpful in understanding the features of the present invention, and therefore sometimes differ from the actual dimensions.

[0023] One embodiment of the balloon catheter of the present invention has the following features: a balloon body having an expansion portion, a distal cannula portion located distal to the expansion portion, and a proximal cannula portion located closer to the position than the expansion portion. The distal cannula portion has a fixing portion fixed to the axis. A reinforcing portion is provided on a portion of the inner surface of the distal cannula portion near the position than the distal end of the fixing portion, and in a circumferential direction. The inner surface of the proximal cannula portion does not have the reinforcing portion. By having a reinforcing portion on a portion of the inner surface of the distal cannula portion near the position than the distal end of the fixing portion, and in a circumferential direction, the rigidity of the distal cannula portion can be increased while suppressing its outer diameter. This mitigates the rigidity gradient difference between the distal cannula portion and the fixing portion, resulting in prevention of balloon kinking, buckling, or compression along the long side during balloon catheter operations such as delivery to the lesion and treatment. Furthermore, the distal cannula has a reinforcing section on its inner surface, ensuring that the fluid reaches its final destination when pressurized fluid or other fluids are introduced into the balloon to inflate it. This rigidity of the distal cannula, which bears the fluid, helps to suppress elongation of the balloon along its long axis. Conversely, the proximal cannula lacks a reinforcing section on its inner surface. This ensures that the lumen of the proximal cannula, which serves as the fluid inlet and outlet, does not narrow when the balloon is inflated or deflated by the introduction or removal of fluid. Therefore, treatment delays are avoided by not prolonging the fluid introduction and removal time (inflation and deflation time). Hereinafter, the balloon catheter / balloon will sometimes be referred to simply as a "balloon".

[0024] Reference Figures 1-7 The balloon catheter is explained. Figure 1 A side view of a balloon catheter according to one embodiment of the present invention is shown. Figure 2 Show Figure 1 A cross-sectional view along the long axis of the distal portion of the balloon catheter shown. Figure 3 A cross-sectional view along the long axis of the distal portion of a balloon catheter according to another embodiment of the present invention is shown. Figure 4 A cross-sectional view along the long axis of the distal portion of a balloon catheter according to another embodiment is shown. Figure 5 Show Figure 1 VV sectional view, Figure 6 Showing the representation Figure 5 A cross-sectional view of a modified example. Figure 7 Show Figure 1 Sectional view VII-VII.

[0025] like Figure 1As shown, the balloon catheter 1 has an axis 3 and a balloon 2 positioned outside the axis 3. The balloon catheter 1 has a proximal side and a distal side, with the balloon 2 positioned distal to the axis 3. Furthermore, relative to the extension direction of the balloon catheter 1 or the long axis direction of the axis 3, the proximal side refers to the direction proximal to the user or surgeon, and the distal side refers to the opposite direction of the proximal side, i.e., the direction to the side of the treatment object.

[0026] like Figures 1-7 As shown, the balloon 2 for the balloon catheter has a balloon body 20. The balloon body 20 has an expansion portion 20e, a distal cannula portion 25 located distal to the expansion portion 20e, and a proximal cannula portion 21 located closer to the position than the expansion portion 20e. The distal cannula portion 25 has a fixing portion 25f fixed to the shaft 3. A reinforcing portion 60 is provided on a portion of the inner surface of the distal cannula portion 25 closer to the position than the distal end of the fixing portion 25f and in a circumferential direction. The inner surface of the proximal cannula portion 21 does not have a reinforcing portion 60.

[0027] The expansion portion 20e in the balloon body 20 is the part that can expand by introducing fluid. The proximal cannula portion 21 and the distal cannula portion 25 are non-expanding portions located closer to the proximal and distal sides of the expansion portion 20e, respectively. The distal cannula portion 25 has a fixing portion 25f that is fixed to the shaft 3. The shaft 3 has a fluid flow path internally, and more preferably, it has a guidewire insertion path. To form a structure in which the shaft 3 has a fluid flow path and a guidewire insertion path internally, for example, as... Figures 2-4 As shown, the following structure can be described: the shaft 3 has an outer tube 31 and an inner tube 32. The inner tube 32 functions as the insertion passage for the guidewire, and the space between the inner tube 32 and the outer tube 31 functions as a fluid flow path. When the shaft 3 has an outer tube 31 and an inner tube 32, it is preferable that the inner tube 32 extends and protrudes from the distal end of the outer tube 31 and penetrates to a position distal to the balloon 2. The inner surface of the distal sheath portion 25 is fixed to the inner tube 32 at the fixing portion 25f, and the inner surface of the proximal sheath portion 21 is fixed to the outer tube 31. In this case, it is preferable that at least a portion of the proximal sheath portion 21 and at least a portion of the distal sheath portion 25 are fixed to the shaft 3 by means of welding or the like. The distal sheath portion 25 and the inner tube 32 of the shaft 3 can be directly fixed or indirectly fixed via the reinforcing portion 60. Furthermore, the distal sheath portion 25 and the inner tube 32 can be fixed as follows: Figure 2 As shown, it can be fixed via other pipes or other fixing components 33, or as... Figure 3 As shown, the fixing is achieved by welding other resins 34. The fixing part 25f includes both a portion fixed by the resin 34 and a portion fixed by the resin 34 and the reinforcing part 60. Additionally, as... Figure 4As shown, the distal sheath 25 and the inner tube 32 can also be fixed along the entire long axis of the fixing part 25f via resin 34 and reinforcement 60. With such a structure, the expansion and contraction of the dilation part 20e can be controlled using a pressurizer (balloon pressurizer). The fluid can also be a pressurized fluid pressurized by a pump or the like.

[0028] By having a reinforcing portion 60 on the inner surface of the distal cannula 25, which is closer to the fixed portion 25f than the distal end and has a circumferential portion therein, the rigidity of the distal cannula 25 can be increased by the reinforcing portion 60 while suppressing the outer diameter of the distal cannula 25. This mitigates the rigidity gradient difference between the portion of the distal cannula 25 closer to the fixed portion and the fixed portion 25f, reducing the likelihood of kinking or buckling at the anterior end of the balloon 2. If kinking or buckling is less likely to occur at the anterior end of the balloon 2, it becomes easier to deliver the balloon catheter 1 to the desired location and perform the desired treatment. Furthermore, the reinforcing portion 60 on the inner surface of the distal cannula 25 increases the rigidity of the distal cannula 25, which is the final destination of the pressurized fluid introduced from the proximal side of the balloon 2, when the balloon 2 is inflated by introducing pressurized fluid into it, thus suppressing elongation of the balloon 2 along its long axis. This allows the balloon 2 to expand sufficiently in the radial direction, reducing the risk of damage caused by the balloon expanding into normal blood vessels that are not intended for treatment. Furthermore, since the inner surface of the proximal cannula portion 21 lacks a reinforcing portion 60, the lumen of the proximal cannula portion 21, which serves as the fluid inlet and outlet to the balloon 2, does not narrow during the introduction and discharge of pressurized fluid into and from the balloon 2. Therefore, the time for fluid introduction and discharge (inflation and deflation time) is not prolonged, thus avoiding treatment delays and reducing the burden on the patient.

[0029] like Figure 2 As shown, the distal cannula portion 25 may also have a reinforcing portion 60 separated from the fixing portion 25f. That is, the distal end of the reinforcing portion 60 may also be positioned closer to the position than the proximal end of the fixing portion 25f. If the reinforcing portion 60 is separated from the fixing portion 25f, the rigidity of the distal cannula portion 25 can be improved without compromising the flexibility of the balloon 2, and a balloon 2 that is flexible yet not prone to kinking or buckling can be formed. Alternatively, the reinforcing portion 60 may be continuously provided with the fixing portion 25f. If the reinforcing portion 60 is continuously provided, the rigidity of the distal cannula portion 25 can be further improved, and a balloon 2 that is even less prone to kinking or buckling can be formed. In addition, as Figure 3 and Figure 4 As shown, the distal sleeve portion 25 may also have a reinforcing portion in the fixing portion 25f, such as... Figure 4 As shown, the reinforcing part 60 can also be continuously provided from the proximal side to the distal side of the fixing part 25f. Additionally, as...Figure 4 As shown, the distal sleeve portion 25 only needs to have a reinforcing portion 60 near the distal end of the fixed portion 25f, or it can also have a reinforcing portion 60 near the distal end of the fixed portion 25f. This can further improve the rigidity of the distal sleeve portion 25.

[0030] The balloon 2 for the balloon catheter preferably has a reinforcing portion 60 at least 10% of the length of the distal cannula portion 25 in the long axis direction, more preferably at 15% or more, and even more preferably at 20% or more. Alternatively, the balloon 2 for the balloon catheter may have a reinforcing portion 60 in 100% of the length of the distal cannula portion 25 in the long axis direction, preferably at 95% or less, more preferably at 90% or less, and even more preferably at 85% or less. If the balloon 2 for the balloon catheter has a reinforcing portion 60 on the inner surface of the distal cannula portion 25 within the above-mentioned range, the rigidity of the distal cannula portion 25 can be improved.

[0031] When a reinforcing portion 60 is provided on a portion of the distal sheath portion 25 in the long axis direction, it is preferable that the reinforcing portion 60 is provided on the proximal end side of the distal sheath portion 25. For example, the reinforcing portion 60 is preferably provided in the long axis direction for 90% or more of the portion closer to the midpoint of the distal sheath portion 25, more preferably 95% or more, and may also be provided for 100%. In this case, the reinforcing portion 60 may not be provided in the portion further distal to the midpoint of the distal sheath portion 25 in the long axis direction, or it may be provided for 5% or more, 10% or more, or 15% or more of the portion further distal to the midpoint of the distal sheath portion 25, or it may be provided for less than 50%, 40% or less, or 30% or less of the portion further distal to the midpoint of the distal sheath portion 25. Therefore, when pressurized fluid is introduced into the balloon 2 to expand the balloon 2, the rigidity of the inlet side of the distal sleeve portion 25, which bears the pressurized fluid introduced from the proximal side of the balloon 2, can be improved, and the suppression of elongation in the long axis direction of the balloon 2 becomes easier.

[0032] When a reinforcing portion 60 is provided on a portion of the distal sheath portion 25 in the long axis direction, it is preferable that the distal end of the reinforcing portion 60 is positioned closer to the position side than the distal end of the fixing portion 25f, and the proximal end of the reinforcing portion 60 is positioned closer to the position side than the proximal end of the fixing portion 25f. This allows the inner surface of the distal sheath portion 25 to be arranged sequentially from the proximal side in the long axis direction in the order of the portion having the reinforcing portion 60, the portion having both the reinforcing portion 60 and the fixing portion 25f, and the portion having the fixing portion 25f, thus making the rigidity change of the distal sheath portion 25 more gradual. As a result, the rigidity gradient difference of the distal sheath portion 25 can be mitigated, making it less prone to kinking or buckling of the anterior end of the balloon 2.

[0033] Alternatively, when a reinforcing portion 60 is provided on a part of the distal sleeve portion 25 in the long axis direction, the distal end of the reinforcing portion 60 may be positioned closer to the proximal end of the fixing portion 25f. In this case, as described above, the distal end of the reinforcing portion 60 may be separated from the proximal end of the fixing portion 25f. Alternatively, the distal end of the reinforcing portion 60 may be configured to contact the proximal end of the fixing portion 25f. If the distal end of the reinforcing portion 60 is configured to contact the proximal end of the fixing portion 25f, the distal sleeve portion 25 can continuously have a portion with increased rigidity due to the reinforcing portion 60 and a portion with increased rigidity due to the fixing portion 25f, thus making the rigidity change of the distal sleeve portion 25 smoother. As a result, the rigidity gradient difference of the distal sleeve portion 25 can be mitigated, making it less likely for kinking or buckling of the anterior end of the balloon 2 to occur.

[0034] The shape of the cross-section of the reinforcing part 60 perpendicular to the major axis can be any shape, or it can be approximately triangular. Figure 5 The approximate rectangle shown Figure 6 The shapes shown are generally trapezoidal, polygonal, sector-shaped, wedge-shaped, convex, spindle-shaped, etc. In a radial section perpendicular to the long axis of the balloon body 20, when the maximum length of the reinforcing portion 60 on the straight line connecting the center of the balloon body 20 and the circumference of the balloon body 20 is set as the height L2 of the reinforcing portion 60, the height L2 of the reinforcing portion 60 is preferably more than 1 times the membrane thickness of the balloon body 20, more preferably more than 1.5 times, and even more preferably more than 2 times. It is also permissible to have less than 50 times, less than 30 times, or less than 10 times. By having such a height L2, the rigidity of the distal sheath portion 25 can be improved. Furthermore, in a radial section perpendicular to the long axis of the reinforcing portion 60, the reinforcing portion 60 has a circumferential length L1 of the balloon 2, preferably L2 > L1. This further improves the rigidity of the distal sheath portion 25. Alternatively, L1 and L2 can be L2 > 0.8L1, L2 > 0.5L1, or L2 > 0.3L2. If L1 and L2 satisfy the above relationship, the rigidity of the distal sleeve portion 25 can be improved. Alternatively, the reinforcing portion 60 can also be configured such that L2 < L1. With such a structure, a balance can be achieved between the rigidity of the portion of the distal sleeve portion 25 with the reinforcing portion 60 and the portion without the reinforcing portion 60, and the overall rigidity can be appropriate.

[0035] like Figure 5 As shown, the balloon 2 for the balloon catheter may also have a circumferential reinforcement 60 on the inner surface of the distal cannula portion 25. Additionally, as... Figure 6As shown, the balloon 2 for the balloon catheter may also have multiple reinforcing portions 60 in the circumferential direction on the inner surface of the distal cannula portion 25. When multiple reinforcing portions 60 are provided, it is preferable that the reinforcing portions 60 are spaced apart circumferentially, and more preferably arranged at equal intervals circumferentially. By having multiple reinforcing portions 60 as described above, the rigidity of the distal cannula portion 25 can be uniformly increased circumferentially, preventing kinking, buckling, and elongation of the distal portion of the balloon 2 in any direction.

[0036] Although not illustrated, the balloon 2 for the balloon catheter may have a reinforcing portion 60 discontinuously along the long axis of the balloon body 20 on the inner surface of the distal cannula portion 25 and in a portion of the circumferential direction of the distal cannula portion 25. Alternatively, it may have a reinforcing portion 60 extending spirally relative to the long axis of the balloon body 20. By adjusting the configuration of the reinforcing portion 60 in this way, the rigidity of the distal cannula portion 25 can be adjusted.

[0037] The reinforcing part 60 is preferably made of resin. If the reinforcing part 60 is made of resin, rigidity can be ensured without excessively compromising the flexibility of the distal sheath portion 25. Examples of resins constituting the reinforcing part 60 include polyolefin resins such as polyvinyl chloride, polyethylene, polypropylene, and cyclic polyolefins; polystyrene resins; polymethylpentene resins such as poly-(4-methylpentene-1); polycarbonate resins; acrylic resins; ABS resins; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; butadiene-styrene copolymers; polyamide elastomers; and polyamide resins such as nylon 6, nylon 6.6, nylon 6.10, and nylon 12. Only one type can be used, or two or more types can be used in combination. When the reinforcing part 60 is made of resin, it is preferably fixed to the balloon body 20, for example, by bonding or fusion with an adhesive, and more preferably by fusion. Alternatively, the reinforcing part 60 can be integrally formed with the balloon body 20. If integrally formed, the reinforcing part 60 can be prevented from detaching from the balloon body 20.

[0038] The reinforcing part 60 is preferably made of metal. If the reinforcing part 60 is made of metal, the rigidity of the distal sheath portion 25 can be easily adjusted by varying the shape, number, and arrangement of the reinforcing part 60. Examples of metals constituting the reinforcing part 60 include stainless steel, aluminum, aluminum alloys, titanium, titanium alloys, copper, copper alloys, tantalum, and cobalt alloys. One or more of these can be used. When the reinforcing part 60 is made of metal, it can be fixed to the balloon body 20, for example, by using an adhesive.

[0039] The balloon 2 for balloon catheters preferably does not have a reinforcing portion 60 on the outer surface of the distal cannula portion 25. This allows for the suppression of the outer diameter of the distal cannula portion 25, facilitating easy insertion of the balloon catheter 1 into the body cavity. Alternatively, although not illustrated, the balloon 2 for balloon catheters may have a portion with a reinforcing portion 60 on the outer surface of the distal cannula portion 25. In this case, in a radial section perpendicular to the long axis of the balloon body 20, when the maximum length of the reinforcing portion 60 along the straight line connecting the center of the balloon body 20 and the circumference of the balloon body 20 is defined as the height of the reinforcing portion 60, the height of the reinforcing portion 60 is preferably lower than the height L2 of the reinforcing portion 60 on the inner surface of the distal cannula portion 25. With such a structure, even if the distal cannula 25 has a reinforcing portion 60 on its outer surface, the outer diameter of the distal cannula 25 will not become too large. The rigidity of the distal cannula 25 can be improved by the reinforcing portions 60 on the inner and outer surfaces. This can ensure the insertion of the balloon catheter 1 while further preventing kinking, bending, and elongation of the distal part of the balloon 2.

[0040] like Figure 7 As shown, the balloon 2 for the balloon catheter does not have a reinforcing portion 60 on the inner surface of the proximal cannula portion 21. This ensures sufficient lumen coverage of the proximal cannula portion 21, allowing fluid to easily pass through the lumen of the proximal cannula portion 21, which serves as the inlet and outlet to the balloon 2, during the introduction and drainage of pressurized fluid into and from the balloon 2. This shortens the fluid introduction and drainage time and reduces the burden on the patient.

[0041] Although not illustrated, the balloon 2 for the balloon catheter may also have a reinforcing portion 60 on the outer surface of the proximal cannula portion 21 and on a portion of the circumferential direction of the proximal cannula portion 21. If it is on the outer surface of the proximal cannula portion 21, even with the reinforcing portion 60, the introduction and discharge of fluid will not be hindered, and the rigidity of the proximal side of the balloon body 20 can be improved.

[0042] Reference Figure 8 The balloon catheter of other embodiments of the present invention will be described. Figure 8 A cross-sectional view along the long axis of a balloon catheter according to another embodiment of the present invention is shown.

[0043] like Figure 8As shown, the dilation portion 20e preferably has a straight tube portion 23 and a distal conical portion 24 located distal to the straight tube portion 23. Alternatively, it may have a proximal conical portion 22 located closer to the straight tube portion 23. The distal conical portion 24 and the proximal conical portion 22 are preferably formed to decrease in diameter as they move away from the straight tube portion 23. By having a straight tube portion 23 in the dilation portion 20e, the straight tube portion 23 can make sufficient contact with the narrow portion, facilitating the dilation of the narrow portion. Furthermore, the dilation portion 20e has a distal conical portion 24 and a proximal conical portion 22 whose outer diameter decreases as they move away from the straight tube portion 23. This allows the outer diameter of the distal and proximal ends of the balloon 2 to be reduced when the balloon 2 is contracted and wound around the shaft 3, thereby reducing the step difference between the shaft 3 and the balloon 2. As a result, the balloon 2 can be easily inserted into the body cavity.

[0044] On the inner surface of the distal tapered portion 24, in the long axis direction of the expansion portion 20e, at position D0 where the distal end of the distal tapered portion 24 is set to 0%, and at position D1 where the proximal end of the distal tapered portion 24 is set to 100%,... 100 Preferably, a reinforcing portion 60 is provided on the inner surface of the distal conical portion 24 and in a circumferential portion of the distal conical portion 24, in the range from 0% to 10%. The balloon 2, via the balloon catheter, also has a reinforcing portion 60 on the inner surface of the distal conical portion 24 within the aforementioned range, which further improves rigidity without increasing the distal outer diameter of the balloon 2. This also prevents kinking and buckling of the balloon 2 within the distal conical portion 24. Furthermore, since the rigidity of the distal portion of the balloon 2, i.e., the distal conical portion 24 and the distal cannula portion 25, which bear the pressurized fluid, can be ensured, elongation of the balloon 2 in the long axis direction can be further prevented.

[0045] The balloon 2 for the balloon catheter may have a reinforcing portion 60 extending beyond the distal cone 24 from 0% to 10%, or from 15% or more, or from 20% or more. Furthermore, the balloon 2 for the balloon catheter may have a reinforcing portion 60 extending beyond the distal cone 24 from 0% to less than 95%, or from less than 80%, or from less than 70%. If the balloon 2 for the balloon catheter has a reinforcing portion 60 within the aforementioned ranges, the rigidity of the distal cone 24 can be improved.

[0046] Although not illustrated, the balloon 2 for the balloon catheter can have one or more reinforcing portions 60 circumferentially on the inner surface of the distal conical portion 24. When multiple reinforcing portions 60 are present, it is preferable that the reinforcing portions 60 are circumferentially spaced apart, and more preferably arranged at equal intervals circumferentially. By having multiple reinforcing portions 60 as described above, the rigidity of the distal conical portion 24 can be uniformly increased circumferentially, preventing kinking, buckling, and elongation of the distal portion of the balloon 2 in any direction.

[0047] like Figure 8 As shown, preferably, the reinforcing portion 60 of the distal cannula portion 25 and the reinforcing portion 60 of the distal tapered portion 24 extend continuously in the long axis direction of the balloon body 20. By having the reinforcing portion 60 extending continuously in the distal cannula portion 25 and the distal tapered portion 24 of the balloon catheter balloon 2, the axial elongation of the distal portion of the balloon 2 can be further suppressed.

[0048] Materials constituting the balloon body 20 include, for example, polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer; polyester resins such as polyethylene terephthalate and polyester elastomers; polyurethane resins such as polyurethane and polyurethane elastomers; polyphenylene sulfide resins; polyamide resins such as polyamide elastomers; fluorinated resins; silicone resins; and natural rubber such as latex rubber. Only one type may be used, or two or more types may be used in combination. Polyamide resins, polyester resins, and polyurethane resins are preferred. In particular, from the perspective of the balloon body 20's thin-film properties and flexibility, elastomer resins are preferred. For example, among polyamide resins, nylon 12 and nylon 11 are preferred as the resin constituting the balloon body 20, and nylon 12 is more preferred from the perspective of easier molding during blow molding. Furthermore, from the perspective of the balloon body 20's thin-film properties and flexibility, polyamide elastomers such as polyether ester amide elastomers and polyamide ether elastomers are preferred. Among these considerations, polyether ester amide elastomer is preferred because it offers high yield strength and good dimensional stability of the balloon body 20.

[0049] Examples of materials constituting the shaft 3 include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, fluorinated resins, vinyl chloride resins, silicone resins, and natural rubber. Only one type may be used, or two or more may be used in combination. Preferably, the material constituting the shaft 3 is at least one of a polyamide resin, a polyolefin resin, or a fluorinated resin, thereby improving the slippage of the shaft 3 surface and enhancing the insertion portability of the balloon catheter 1 within the body cavity.

[0050] Examples of joining balloon 2 and shaft 3 include bonding with adhesive, fusion bonding, and pressing by installing a ring-shaped component at the overlapping portion of the end of balloon 2 and shaft 3. Preferably, balloon 2 and shaft 3 are joined by fusion bonding. By fusion bonding balloon 2 and shaft 3, the joint between balloon 2 and shaft 3 is less likely to disintegrate even with repeated expansion and contraction of balloon 2, thus easily improving the joint strength between balloon 2 and shaft 3.

[0051] like Figure 1 As shown, a hub 4 can also be provided on the proximal side of axis 3, and a fluid injection section 7 can be provided on the hub 4, the fluid injection section 7 being in communication with the flow path of fluid supplied to the interior of balloon 2. Furthermore, the hub 4 preferably has a guidewire insertion section 5 communicating with the guidewire insertion path. By having a hub 4 with a fluid injection section 7 and a guidewire insertion section 5 in the balloon catheter 1, it is easy to supply fluid to the interior of balloon 2 to inflate and deflate balloon 2, and to deliver balloon catheter 1 along the guidewire to the treatment site. This is not only applicable to so-called over-the-wire type balloon catheters where the guidewire is inserted from the distal side to the proximal side of the axis, but also to so-called quick-exchange type balloon catheters where the guidewire is inserted midway from the distal side of axis 3 to the proximal side.

[0052] The connection between the shaft 3 and the hub 4 can be achieved, for example, by bonding with an adhesive or by fusion. Preferably, the shaft 3 and the hub 4 are joined by adhesive. By bonding the shaft 3 and the hub 4, for example, when the materials constituting the shaft 3 are different from those constituting the hub 4 (e.g., the shaft 3 is made of a highly flexible material and the hub 4 is made of a highly rigid material), the connection strength between the shaft 3 and the hub 4 can be increased, thereby improving the durability of the balloon catheter 1.

[0053] This application claims priority based on Japanese Patent Application No. 2020-190297, filed on November 16, 2020. The entire contents of the description of Japanese Patent Application No. 2020-190297, filed on November 16, 2020, are incorporated herein by reference.

[0054] Explanation of reference numerals in the attached figures

[0055] 1…Balloon catheter; 2…Balloon; 3…Shaft; 4…Gathering device; 5…Guidewire insertion section; 7…Fluid injection section; 20…Balloon body; 20e…Dilation section; 21…Proximal cannula section; 22…Proximal conical section; 23…Straight tube section; 24…Distal conical section; 25…Distal cannula section; 25f…Fixture section; 31…Outer tube; 32…Inner tube; 33…Fixture component; 34…Resin of fixation section; 60…Reinforcement section; D0…0% position; D 100…100% position; L1: circumferential length of the reinforcing balloon; L2: height of the reinforcing section.

Claims

1. A balloon for a balloon catheter, characterized in that, It has a balloon body, The balloon body has an expansion portion, a distal cannula portion located distal to the expansion portion, and a proximal cannula portion located closer to the expansion portion. The distal sleeve portion has a fixing part that is fixed to the shaft. A reinforcing portion is provided on the inner surface of the distal sleeve portion, closer to the distal end of the fixing portion than to the distal end, and in the circumferential direction of the distal sleeve portion. The expansion portion has a straight tube portion and a distal tapered portion located further distal to the straight tube portion. When the distal end of the distal tapered portion is set to 0% and the proximal end of the distal tapered portion is set to 100% in the long axis direction of the expansion portion, there is no reinforcing portion in the interval of the distal tapered portion exceeding 70% and below 100%.

2. The balloon for balloon catheters according to claim 1, characterized in that, The expansion portion has a straight tube portion and a distal tapered portion located further distal to the straight tube portion. On the inner surface of the distal tapered portion, when the distal end of the distal tapered portion is set to 0% in the long axis direction of the expansion portion and the proximal end of the distal tapered portion is set to 100%, the reinforcement portion is present on the inner surface of the distal tapered portion and in a portion of the circumferential direction of the distal tapered portion in the interval from 0% to 10% of the distal tapered portion.

3. The balloon for balloon catheters according to claim 2, characterized in that, The reinforcing portion of the distal cannula and the reinforcing portion of the distal tapered portion extend continuously along the long axis of the balloon body.

4. The balloon catheter according to any one of claims 1 to 3, characterized in that, The reinforcing part is made of resin.

5. The balloon catheter according to any one of claims 1 to 3, characterized in that, The reinforcing part is made of metal.

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