Catheter balloon

Abstract

A balloon catheter (1A) comprises: an expansion part (3B) having a tubular shape extending in the extension direction; a distal end connecting part (3A) extending from the distal end (30D) of the expansion part (3B) to the opposite side of the expansion part (3B); and a proximal end connecting part (3C) extending from the proximal end (30P) of the expansion part (3B) to the opposite side of the expansion part (3B). A balloon (3) has an inner thick film part (4A) and a thin film part (40) differing in thickness from each other. The inner thick film part (4A) is thicker than the thin film part (40). The outer diameter, which is the radial distance from the central axis (C1) extending in the extension direction through the center of the expansion part (3B) to an outer surface (302), is the same in the thin film part (40) as in the inner thick film part (4A). The inner diameter, which is the radial distance from the central axis (C1) to an inner surface (301), is smaller in the inner thick film part (4A) than in the thin film part (40).

Description

[Technical field]

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

[0002] In balloon catheters, the balloon is required to have a high pressure resistance, and various methods for increasing the pressure resistance of the balloon have been proposed. For example, in the balloon catheter described in Patent Document 1, a reinforcing portion is provided on the outer surface of the base balloon to strengthen the base balloon and prevent the base balloon from being overexpanded when pressurized. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6259560 Summary of the Invention [Problem to be solved by the invention]

[0004] When the balloon has a structure with an external thickness, there is a problem that the balloon's passability through the blood vessel is reduced. Also, when the balloon is used to retain a stent in the blood vessel, the thickness of the balloon's exterior makes the balloon more likely to get caught on the stent. In this case, there is a problem that the passability of the balloon when passing through the stent placed in the blood vessel is reduced, or that it may be difficult to detach the balloon from the stent after the stent is expanded by the balloon.

[0005] An object of the present invention is to provide a catheter balloon that can withstand high pressure while maintaining passability within blood vessels. [Means for solving the problem]

[0006] a tip connecting portion which extends from a first tip portion which is an end portion on one side in the extension direction of the expansion portion to the opposite side of the expansion portion, the tip connecting portion having a diameter greater than a diameter of a second tip portion which is the end portion opposite the end connected to the expansion portion, and a base end connecting portion which extends from a first base end which is the end portion on the other side in the extension direction of the expansion portion to the opposite side of the expansion portion, the end portion connected to the expansion portion having a diameter greater than a diameter of a second base end which is the end portion opposite the end connected to the expansion portion, and the catheter balloon according to the present invention has an inner thick membrane portion and a thin membrane portion which have different thicknesses, the inner thick membrane portion is thicker than the thin membrane portion, the inner surface of the inner thick membrane portion protrudes inward in the radial direction centered on a central axis extending in the extension direction through the center of the expansion portion, more than the inner surface of the thin membrane portion, and the outer surface of the inner thick membrane portion does not protrude outward in the radial direction relative to the outer surface of the thin membrane portion.

[0007] The catheter balloon can withstand high pressure because the inner thick membrane portion can suppress sudden expansion. The outer surface of the inner thick membrane portion does not protrude radially outward beyond the outer surface of the thin membrane portion. This allows the catheter balloon to maintain good passability through blood vessels.

[0008] In the present invention, the outer diameter, which is the radial distance from the central axis to the outer surface, may be the same for the thin film portion and the inner thick film portion, and the inner diameter, which is the radial distance from the central axis to the inner surface, may be smaller for the inner thick film portion than for the thin film portion. The outer diameter of the catheter balloon is the same for the inner thick film portion and the thin film portion, and even the inner thick film portion, which is thicker, does not protrude outward. This allows the catheter balloon to maintain better passability through blood vessels.

[0009] In the present invention, the inner thick membrane portion may extend along the stretching direction. The inner thick membrane portion can suppress the catheter balloon from suddenly expanding and contracting in the stretching direction when contracting and expanding. Therefore, the catheter balloon can be prevented from suddenly expanding in the radial direction in response to expansion in the stretching direction, making it possible to achieve high pressure resistance.

[0010] In the present invention, the inflation section may be provided with the inner thick membrane section, and the inner thick membrane section may extend from the first distal end section to the first proximal end section along the stretching direction. The catheter balloon can be prevented from suddenly expanding and contracting in the stretching direction during deflation and expansion over the entire area of ​​the inflation section.

[0011] In the present invention, the expansion section is provided with an outer thick membrane section having a thickness greater than that of the thin membrane section, and the inner thick membrane section, the inner diameter of the thin membrane section and the outer thick membrane section are the same, the outer diameter of the outer thick membrane section is greater than that of the thin membrane section, the inner thick membrane section and the outer thick membrane section are aligned in the stretching direction, and the inner thick membrane section is closer to the first tip section than the outer thick membrane section, and the outer thick membrane section is closer to the first base end section than the inner thick membrane section. The catheter balloon does not have an outer thick membrane section on the tip side of the expansion section. Therefore, compared to a case in which the outer thick membrane section is present over the entire stretching direction of the expansion section, the catheter balloon is less likely to be held in a fully stretched state in the stretching direction. For example, even if the outer thick membrane section gets caught on the stent at the stage of inserting the balloon into a blood vessel in which a stent is placed, the catheter balloon can be prevented from being held in a fully stretched state in the stretching direction. Therefore, it is possible to prevent unnecessary force from being applied to the stent from the catheter balloon.

[0012] In the present invention, the inflation section, the tip connecting section, and the base connecting section may be provided with the inner thick membrane section, and the inner thick membrane section may extend from the second tip section to the second base end section along the stretching direction. The catheter balloon can be prevented from suddenly expanding and contracting in the stretching direction during contraction and expansion over the entire area of ​​the inflation section, the tip connecting section, and the base connecting section.

[0013] In the present invention, the thickness of the inner thick membrane portion of the tip connecting portion may become thinner from a portion connected to the first tip portion of the expansion portion toward the second tip portion, and the thickness of the inner thick membrane portion of the base end connecting portion may become thinner from a portion connected to the first base end of the expansion portion toward the second base end. Since the second tip portion of the tip connecting portion and the second base end of the base end connecting portion of the catheter balloon can be made soft, when these portions come into contact with a stent, a hard lesion, or the like, the catheter balloon can be prevented from being held in a fully stretched state in the extension direction.

[0014] In the present invention, the inner thick membrane portion may be provided with at least one slit. The slit allows the inner thick membrane portion of the catheter balloon to be easily bent, and therefore the catheter balloon can be deformed well even in a tortuous blood vessel. This allows the catheter balloon to follow the blood vessel well.

[0015] In the present invention, a plurality of slits may be arranged in the stretching direction, and the interval between each of the plurality of slits in the stretching direction may be narrower as it approaches the second tip portion. The catheter balloon is easier to bend at the tip side where the interval between the plurality of slits is narrower. In this case, when the catheter balloon enters a meandering blood vessel or the like, the catheter balloon is easier to follow the blood vessel. Therefore, the user can make the catheter balloon properly reach the target site. On the other hand, the catheter balloon has a higher rigidity at the base end side where the interval between the plurality of slits is wider. In this case, the stress applied by the catheter balloon to the lesion of the blood vessel can be increased, thereby improving the treatment efficiency.

[0016] In the present invention, a plurality of slits may be arranged in the stretching direction, and the depth of each of the plurality of slits may be deeper as it approaches the second tip portion. The catheter balloon is easier to bend as the depth of the plurality of slits is deeper at the tip side. In this case, when the catheter balloon enters a meandering blood vessel or the like, the catheter balloon is easier to follow the blood vessel. Therefore, the user can make the catheter balloon properly reach the target site. On the other hand, the catheter balloon has greater rigidity as the depth of the plurality of slits is shallower at the base end side. In this case, the stress applied by the catheter balloon to the lesion of the blood vessel can be increased, thereby improving the treatment efficiency.

[0017] In the present invention, the inner thick membrane portion may be annular and extend in a circumferential direction centered on the central axis. The catheter balloon can maintain high pressure resistance even when the thin membrane portion is thin. In addition, the catheter balloon can improve flexibility when bent in a direction intersecting with the stretching direction.

[0018] In the present invention, the inner thick membrane portion may be in a spiral shape extending in a circumferential direction centered on the central axis, and may be provided between the first distal end portion and the first proximal end portion. Since the inner thick membrane portion can be arranged seamlessly in the extension direction of the expansion portion, the catheter balloon can maintain high pressure resistance in the extension direction of the expansion portion. In addition, the flexibility of the catheter balloon can be improved.

[0019] In the present invention, the inner thick membrane portion may be provided across the entire area between the second distal end and the second proximal end. Since the inner thick membrane portion can be seamlessly disposed across the entire area between the second distal end and the second proximal end, the catheter balloon can maintain high pressure resistance over a wider range in the stretching direction.

[0020] In the present invention, at least one slit may be provided in the inner thick membrane portion. The slit allows the inner thick membrane portion of the catheter balloon to be bent, so that the catheter balloon can be deformed well even in a tortuous blood vessel. This allows the catheter balloon to follow the blood vessel well.

[0021] In the present invention, a plurality of slits may be provided arranged in the direction in which the inner thick membrane portion extends, and each of the plurality of slits may be arranged at a position overlapping at least one of the other slits when viewed from the extension direction. The catheter balloon may be provided with a portion having high flexibility and a portion having low flexibility in the circumferential direction. In this case, when the catheter balloon enters a meandering blood vessel or the like, the catheter balloon is more likely to follow the blood vessel. Therefore, the user can make the catheter balloon reach the desired site appropriately. [Brief description of the drawings]

[0022] [Figure 1] 1A is a diagram showing a balloon catheter 1A and a cross-sectional view of the balloon catheter 1A taken along a plane perpendicular to the extension direction. FIG. [Diagram 2] 1A is a diagram showing a balloon catheter 1B and a cross-sectional view of the balloon catheter 1B taken along a plane perpendicular to the stretching direction. FIG. [Diagram 3] 1A is a diagram showing a balloon catheter 1C and a cross-sectional view of the balloon catheter 1C taken along a plane parallel to the stretching direction. FIG. [Figure 4] 1A is a diagram showing a balloon catheter 1D and a cross-sectional view of the balloon catheter 1D taken along a plane parallel to the extension direction. FIG. [Diagram 5] 1A is a diagram showing a balloon catheter 1E and a cross-sectional view of the balloon catheter 1E cut along a plane perpendicular to the stretching direction. FIG. [Figure 6] 1A is a diagram showing a balloon catheter 1F and a cross-sectional view of the balloon catheter 1F cut along a plane parallel to the stretching direction. FIG. [Figure 7]1A is a diagram showing a balloon catheter 1G and a cross-sectional view of the balloon catheter 1G cut along a plane perpendicular to the extension direction. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Embodiments (1A to 1G) of a balloon catheter 1 according to the present invention will be described with reference to the drawings. The drawings referred to are used to explain technical features that can be adopted by the present invention. The configurations of the device described are merely illustrative examples and are not intended to limit the scope of the present invention. The balloon catheter 1 can dilate stenotic lesions formed in blood vessels with the balloon 3, or can expand a stent within the blood vessel.

[0024] <First embodiment (balloon catheter 1A)> A balloon catheter 1A will be described with reference to Fig. 1. The balloon catheter 1A has a catheter shaft 2 and a balloon 3.

[0025] <Catheter shaft 2> The balloon 3 is connected to one end of a tubular catheter shaft 2. The balloon catheter 1A is used with a hub (not shown) connected to the other end of the catheter shaft 2. The hub is capable of supplying compressed fluid to the balloon 3 via the catheter shaft 2.

[0026] Hereinafter, one of the two ends of the catheter shaft 2 will be referred to as the "tip side." The other of the two ends of the catheter shaft 2 will be referred to as the "base side." The direction extending along the catheter shaft 2 will be referred to as the "extension direction." The axis extending in the extension direction through the center of the catheter shaft 2 will be referred to as the central axis C1. In a cross section taken along a plane perpendicular to the central axis C1 (hereinafter simply referred to as a "cross section"), in the radial direction centered on the central axis C1, the side closer to the central axis C1 will be referred to as the "inner side," and the side away from the central axis C1 will be referred to as the "outer side."

[0027] The catheter shaft 2 has an outer tube 21 and an inner tube 22. The outer tube 21 and the inner tube 22 are each flexible. The inner diameter of the outer tube 21 is larger than the outer diameter of the inner tube 22. The inner tube 22 is disposed in the lumen of the outer tube 21, except for a predetermined portion on the tip side. The predetermined portion on the tip side of the inner tube 22 protrudes from the tip side end (hereinafter referred to as the "tip 211") of the outer tube 21 toward the tip side. The tip side end (hereinafter referred to as the "tip 221") of the inner tube 22 is disposed on the tip side of the tip 211 of the outer tube 21. Hereinafter, the predetermined portion on the tip side of the inner tube 22 is referred to as the "protruding portion 225". The material of the outer tube 21 and the inner tube 22 is not particularly limited, but a polyamide resin is used as an example.

[0028] A compressed fluid supplied from the hub flows through the space in the lumen of the outer tube 21 other than the lumen of the inner tube 22. A guide wire (not shown) is inserted through the lumen of the inner tube 22.

[0029] <Balloon 3> The balloon 3 can be deformed between a contracted state and an expanded state by changing the internal pressure depending on the presence or absence of a supply of compressed fluid through a hub (not shown). FIG. 1 shows the balloon 3 in an expanded state. The distal end of the balloon 3 (hereinafter referred to as "distal end 3D") is connected to the vicinity of the distal end 221 of the protruding portion 225 of the inner tube 22 by thermal welding. The proximal end of the balloon 3 (hereinafter referred to as "proximal end 3P") is connected to the vicinity of the distal end 211 of the outer tube 21 by thermal welding. The balloon 3 covers the protruding portion 225 of the inner tube 22 from the outside. The material of the balloon 3 is not particularly limited, but a polyamide resin is used as an example.

[0030] In the balloon 3, a tip connecting portion 3A, an expansion portion 3B, and a base end connecting portion 3C are defined. The tip connecting portion 3A is a region of the balloon 3 in an expanded state that extends from the tip end 3D to the base end 3P while expanding in diameter. The base end connecting portion 3C is a region of the balloon 3 in an expanded state that extends from the base end 3P to the tip end 3D while expanding in diameter. The expansion portion 3B is a region sandwiched between the tip connecting portion 3A and the base end connecting portion 3C in the balloon 3 in an expanded state, and has a substantially constant diameter along the stretching direction. In an expanded state, the expansion portion 3B is a cylindrical shape extending in the stretching direction. The balloon 3 has an inner surface 301 and an outer surface 302. The radial distance between the central axis C1 and the inner surface 301 is called the inner radius Ri(n) (n is an integer). The radial distance between the central axis C1 and the outer surface 302 is called the outer radius Ro(n).

[0031] The tip end of the expansion section 3B is referred to as the "tip end 30D" and the base end end is referred to as the "base end 30P". The tip connecting section 3A extends from the end connected to the tip end 30D of the expansion section 3B toward the tip end 3D. The diameter of the cross section of the tip connecting section 3A is largest at the end connected to the tip end 30D of the expansion section 3B and is smallest at the tip end 3D. The base end connecting section 3C extends from the end connected to the base end 30P of the expansion section 3B toward the base end 3P. The diameter of the cross section of the base end connecting section 3C is largest at the end connected to the base end 30P of the expansion section 3B and is smallest at the base end 3P.

[0032] The expansion portion 3B has inner thick membrane portions 41, 42, 43 (hereinafter, when they are not distinguished from each other, they are referred to as "inner thick membrane portion 4A") and a thin membrane portion 40. The inner thick membrane portion 4A and the thin membrane portion 40 have different thicknesses. The thickness of the inner thick membrane portion 4A is greater than the thickness of the thin membrane portion 40. The outer diameter Ro(1) of the expansion portion 3B is the same for the inner thick membrane portion 4A and the thin membrane portion 40. Therefore, the outer surface 302 of the expansion portion 3B is smooth without any irregularities. On the other hand, the inner diameter Ri(n) of the expansion portion 3B is different for the inner thick membrane portion 4A and the thin membrane portion 40. The inner diameter Ri(1) of the inner thick membrane portion 4A is smaller than the inner diameter Ri(2) of the thin membrane portion 40. Therefore, the inner surface 301 of the expansion portion 3B protrudes inward in the inner thick membrane portion 4A. Hereinafter, this portion is referred to as the "protruding portion 300". The protrusion 300 is curved in a convex shape toward the central axis C1.

[0033] The inner thick membrane portion 4A extends in the extension direction from the tip end 30D to the base end 30P of the expanding portion 3B. The inner thick membrane portions 41, 42, 43 are arranged at equal intervals in the circumferential direction centered on the central axis C1. The inner diameter Ri(1) of the inner thick membrane portion 4A is uniform from the tip end 30D to the base end 30P. In other words, the protrusion amount of the protrusion portion 300 formed on the inner surface 301 of the inner thick membrane portion 4A toward the central axis C1 is uniform from the tip end 30D to the base end 30P.

[0034] The thin film portion 40 is disposed between the inner thick film portions 41, 42, between the inner thick film portions 42, 43, and between the inner thick film portions 43, 41 in the circumferential direction.

[0035] <Actions and Effects of the First Embodiment> In the balloon catheter 1A, the thickness of the expansion portion 3B of the balloon 3 is greater in the inner thick membrane portion 4A than in the thin membrane portion 40. Therefore, the balloon 3 can withstand high pressure because the inner thick membrane portion 4A can suppress sudden expansion. The outer diameter Ro(1) of the balloon 3 is the same in the inner thick membrane portion 4A and the thin membrane portion 40, and even the thicker inner thick membrane portion 4A does not protrude outward. Therefore, the balloon catheter 1A can maintain good passability of the balloon 3 through the blood vessel.

[0036] The inner thick membrane portion 4A provided in the expansion portion 3B can suppress the sudden expansion and contraction of the balloon 3 in the stretching direction during contraction and expansion. Therefore, the balloon catheter 1A can suppress the tip connecting portion 3A, the expansion portion 3B, and the base connecting portion 3C from suddenly expanding in the radial direction in response to the expansion of the balloon 3 in the stretching direction, making it possible to achieve high pressure resistance.

[0037] The inner thick membrane portion 4A extends in the stretching direction between the tip end 30D and the base end 30P of the expansion portion 3B. Therefore, the balloon catheter 1A can suppress sudden expansion and contraction of the balloon 3 in the stretching direction during contraction and expansion over the entire expansion portion 3B. Furthermore, the balloon catheter 1A can reduce stress on blood vessels in a normal state by suppressing an increase in the diameter of the balloon 3 during expansion, particularly in the expansion portion 3B. Furthermore, the balloon catheter 1A can improve the durability of the expansion portion 3B of the balloon 3.

[0038] <Special Notes on the First Embodiment> The shape of the inflatable portion 3B of the balloon 3 is not limited to a cylindrical shape. The diameter of the inflatable portion 3B may vary along the stretching direction. The cross-sectional shape of the inflatable portion 3B is not limited to a circular shape, but may be an ellipse or a polygon. In this case, the outer diameter Ro(1) of the inflatable portion 3B does not have to be the same between the inner thick portion 4A and the thin portion 40.

[0039] The shape of the inner thick membrane portion 4A is not limited to the above embodiment, and various modifications are possible. The number of inner thick membrane portions 4A extending in the stretching direction is not limited to three, and may be one, two, four or more. The inner thick membrane portion 4A does not have to be provided across the expanding portion 3B between the tip end portion 30D and the base end portion 30P. For example, the inner thick membrane portion 4A may be divided at a portion in the stretching direction.

[0040] Of the protrusions 300 formed on the inner surface 301 of the inner thick membrane portion 4A, the tip end close to the central axis C1 may be sharp or smooth. The thickness of the inner thick membrane portion 4A may become thinner as it approaches the tip end 30D. The thickness of the inner thick membrane portion 4A may become thinner as it approaches the base end 30P.

[0041] <Second embodiment (balloon catheter 1B)> The balloon catheter 1B will be described with reference to Fig. 2. The balloon catheter 1B differs from the balloon catheter 1A in that an inner thick membrane portion 4B is provided not only in the expansion portion 3B of the balloon 3 but also in the distal connecting portion 3A and the proximal connecting portion 3C.

[0042] The tip connecting portion 3A, the expanding portion 3B, and the base connecting portion 3C have inner thick membrane portions 44, 45, 46 (hereinafter, when not distinguishing between them, they are referred to as "inner thick membrane portion 4B") and a thin film portion 40. The inner thick membrane portion 4B extends along the extension direction from the tip portion 3D of the tip connecting portion 3A to the base portion 3P of the base connecting portion 3C. The thickness of the inner thick membrane portion 4B in the expanding portion 3B is uniform from the tip portion 30D to the base portion 30P. Therefore, the inner diameter Ri(1) of the inner thick membrane portion 4B is uniform from the tip portion 30D to the base portion 30P. In other words, the amount of inward protrusion of the protrusion portion 300 formed on the inner surface 301 of the inner thick membrane portion 4B is uniform from the tip portion 30D to the base portion 30P.

[0043] On the other hand, the thickness of the inner thick membrane portion 4B in the tip connecting portion 3A gradually becomes thinner from the portion of the tip connecting portion 3A that connects to the tip portion 30D of the expanding portion 3B toward the tip portion 3D. In other words, the amount of inward protrusion of the protrusion 300 formed on the inner surface 301 of the inner thick membrane portion 4B gradually becomes smaller from the tip portion 30D toward the tip portion 3D.

[0044] The thickness of the inner thick membrane portion 4B at the base end connecting portion 3C gradually becomes thinner from the portion of the base end connecting portion 3C that connects to the base end portion 30P of the expanding portion 3B toward the base end portion 3P. In other words, the amount of protrusion of the protrusion portion 300 formed on the inner surface 301 of the inner thick membrane portion 4B toward the central axis C1 gradually becomes smaller from the base end portion 30P toward the base end portion 3P.

[0045] <Actions and Effects of the Second Embodiment> In the balloon catheter 1B, an inner thick membrane portion 4B is provided from the distal end 3D of the distal end connecting portion 3A to the proximal end 3P of the proximal end connecting portion 3C of the balloon 3. In this case, the balloon catheter 1B can suppress sudden expansion and contraction in the stretching direction during contraction and expansion not only over the entire expansion portion 3B but also over the entire distal end connecting portion 3A and the proximal end connecting portion 3C.

[0046] The thickness of the inner thick membrane portion 4B of the tip connecting portion 3A gradually decreases from the portion connected to the tip end 30D of the expansion portion 3B toward the tip end 3D. The thickness of the inner thick membrane portion 4B of the base end connecting portion 3C gradually decreases from the portion connected to the base end 30P of the expansion portion 3B toward the base end 3P. In this case, the balloon catheter 1B can soften the tip end 3D of the tip connecting portion 3A and the base end 3P of the base end connecting portion 3C of the balloon 3. Therefore, when these portions come into contact with a stent, a hard lesion, etc., the balloon 3 can be prevented from being held in a fully stretched state in the extension direction. Therefore, it is possible to prevent unnecessary force from the balloon 3 from acting on the stent, a hard lesion, etc.

[0047] <Special Notes on the Second Embodiment> The balloon 3 may have an inner thick membrane portion 4B only at the tip connecting portion 3A, and may not have an inner thick membrane portion 4B at the base connecting portion 3C. The balloon 3 may have an inner thick membrane portion 4B only at the base connecting portion 3C, and may not have an inner thick membrane portion 4B at the tip connecting portion 3A. The thickness of the inner thick membrane portion 4B of the tip connecting portion 3A may be uniform from the portion connecting to the tip portion 30D of the inflating portion 3B to the tip portion 3D. The thickness of the inner thick membrane portion 4B of the base connecting portion 3C may be uniform from the portion connecting to the base end portion 30P of the inflating portion 3B to the base end portion 3P.

[0048] <Third embodiment (balloon catheter 1C)> Balloon catheter 1C will be described with reference to Fig. 3. Balloon catheter 1C differs from balloon catheter 1A in that balloon catheter 1C has inner thick membrane portion 4C in an expansion portion 3B, the inner thick membrane portion 4C having a different shape from inner thick membrane portion 4A (see Fig. 1).

[0049] The expansion portion 3B has inner thick membrane portions 51, 52, 53, 54 (hereinafter, when not distinguishing between them, they will be referred to as "inner thick membrane portion 4C") and a thin film portion 40. The inner thick membrane portion 4C extends in an annular shape along the circumferential direction centered on the central axis C1. The inner thick membrane portions 51, 52, 53, 54 are arranged at equal intervals in the extension direction. The thicknesses of the inner thick membrane portions 51, 52, 53, 54 are uniform along the circumferential direction. Therefore, the inner diameter Ri(1) of the inner thick membrane portion 4C is uniform along the circumferential direction. In other words, the protrusion amount of the protrusion portion 300 formed on the inner surface 301 of the inner thick membrane portion 4C toward the central axis C1 is uniform along the circumferential direction.

[0050] <Actions and Effects of the Third Embodiment> Since the inner thick membrane portion 4C of the balloon catheter 1C extends in an annular shape, the high pressure resistance of the balloon 3 can be maintained over the entire circumferential area of ​​the expansion portion 3B even when the thin membrane portion 40 is thin. In addition, the balloon catheter 1C can improve the flexibility when the balloon 3 is bent in a direction intersecting the stretching direction.

[0051] <Special Notes on the Third Embodiment> The number of the inner thick membrane portion 4C is not limited to the above embodiment, and may be 1 to 3, 5 or more. A part of the circumferential direction of the inner thick membrane portion 4C may be divided. The thickness of each of the inner thick membrane portions 51 to 54 may be different. For example, the thickness of the inner thick membrane portions 51 to 54 may become thinner as they approach the tip portion 30D of the expansion portion 3B. The thickness of each of the inner thick membrane portions 51 to 54 in the circumferential direction may not be uniform. An inner thick membrane portion (for example, the inner thick membrane portion 4A in the first embodiment) connecting the inner thick membrane portions 51 to 54 may extend in the extension direction. The annular inner thick membrane portion 4C may also be provided in the tip connecting portion 3A and the base end connecting portion 3C.

[0052] <Fourth embodiment (balloon catheter 1D)> The balloon catheter 1D will be described with reference to Fig. 4. The balloon catheter 1D differs from the balloon catheter 1B in that the distal end connecting portion 3A, the expanding portion 3B, and the proximal end connecting portion 3C have an inner thick membrane portion 4D having a different shape from the inner thick membrane portion 4B (see Fig. 2).

[0053] The tip connecting portion 3A, the expanding portion 3B, and the base end connecting portion 3C have an inner thick film portion 4D and a thin film portion 40. The inner thick film portion 4D extends in a spiral shape along the circumferential direction centered on the central axis C1. The inner thick film portion 4D is provided between the tip end 30D and the base end 30P of the expanding portion 3B, between the tip end 3D and the portion of the tip connecting portion 3A that is connected to the tip end 30D of the expanding portion 3B, and between the base end 3P and the portion of the base end connecting portion 3C that is connected to the base end 30P of the expanding portion 3B. In other words, the inner thick film portion 4D extends in a spiral shape between the tip end 3D of the tip connecting portion 3A and the base end 3P of the base end connecting portion 3C.

[0054] The thickness of the inner thick membrane portion 4D is uniform over the entire area from the tip portion 3D to the base end 3P. Therefore, the inner diameter Ri(1) of the inner thick membrane portion 4D is uniform over the entire area from the tip portion 3D to the base end 3P. In addition, the helical pitch of the inner thick membrane portion 4D is uniform over the entire area from the tip portion 3D to the base end 3P.

[0055] <Actions and Effects of the Fourth Embodiment> The balloon catheter 1D has a spiral inner thick membrane portion 4D in the expansion portion 3B. Therefore, the balloon catheter 1D can arrange the inner thick membrane portion 4D seamlessly along the extension direction of the expansion portion 3B. Therefore, the balloon catheter 1D can maintain the high pressure resistance of the balloon 3 along the extension direction of the expansion portion 3B. In addition, the balloon catheter 1D can improve the flexibility when the expansion portion 3B of the balloon 3 is bent in a direction intersecting the extension direction.

[0056] The balloon catheter 1D further has a spiral inner thick membrane portion 4D in the distal end connecting portion 3A and the proximal end connecting portion 3C. Therefore, the inner thick membrane portion 4D extends between the distal end 30D of the distal end connecting portion 3A and the proximal end 3P of the proximal end connecting portion 3C. In this case, the balloon catheter 1D can have the inner thick membrane portion 4D disposed seamlessly over the entire area of ​​the balloon 3 in the stretching direction between the distal end 3D and the proximal end 3P. Therefore, the balloon catheter 1D can maintain the high pressure resistance of the balloon 3 over a wider area in the stretching direction.

[0057] <Special Notes on the Fourth Embodiment> The inner thick membrane portion 4D may be provided only in the expansion portion 3B, and may not be provided in the tip connecting portion 3A and the base connecting portion 3C. The thickness of the inner thick membrane portion 4D may not be uniform. For example, the thickness of the inner thick membrane portion 4D may become smaller as it approaches the tip portion 30D or the base end portion 30P. The helical pitch of the inner thick membrane portion 4D may not be uniform. For example, the helical pitch of the inner thick membrane portion 4D may become smaller as it approaches the tip portion 30D or the base end portion 30P.

[0058] <Fifth embodiment (balloon catheter 1E)> The balloon catheter 1E will be described with reference to Fig. 5. The balloon catheter 1E differs from the balloon catheter 1A in that the balloon catheter 1E has an inner thick membrane portion 4E and an outer thick membrane portion 6E in the expansion portion 3B instead of the inner thick membrane portion 4A (see Fig. 1). Hereinafter, the center position of the expansion portion 3B of the balloon 3 in the extension direction will be referred to as the "center position Pc".

[0059] The expansion portion 3B has inner thick membrane portions 61, 62, 63 (hereinafter, when not distinguished from one another, they will be referred to as "inner thick membrane portion 4E"), outer thick membrane portions 64, 65, 66 (hereinafter, when not distinguished from one another, they will be referred to as "outer thick membrane portion 6E"), and a thin film portion 40.

[0060] The inner thick membrane portions 61, 62, and 63 are disposed at equal intervals in the circumferential direction around the central axis C1. The inner thick membrane portion 4E extends along the extension direction between the tip portion 30D and the central position Pc of the expanding portion 3B. That is, the inner thick membrane portion 4E is disposed at a position closer to the tip portion 30D than the central position Pc. The outer diameter Ro(1) of the portion of the expanding portion 3B closer to the tip portion 30D than the central position Pc is the same for the inner thick membrane portion 4E and the thin film portion 40. Therefore, the outer surface 302 of this portion is smooth without unevenness. On the other hand, the inner diameter Ri(n) of the portion of the expanding portion 3B closer to the tip portion 30D than the central position Pc is different between the inner thick membrane portion 4E and the thin film portion 40. The inner diameter Ri(1) of the inner thick membrane portion 4E is smaller than the inner diameter Ri(2) of the thin film portion 40. Therefore, the inner surface 301 of this portion protrudes inward in the inner thick membrane portion 4E, and a protrusion 300 is formed.

[0061] The thickness of the inner thick membrane portion 4E is uniform from the tip 30D to the central position Pc. Therefore, the inner diameter Ri(1) of the inner thick membrane portion 4E is uniform from the tip 30D to the central position Pc. In other words, the protrusion amount of the protrusion 300 formed on the inner surface 301 of the inner thick membrane portion 4E toward the central axis C1 is uniform from the tip 30D to the central position Pc.

[0062] The outer thick film portion 6E has a thickness different from that of the thin film portion 40 and coincides with that of the inner thick film portion 4E. The thickness of the outer thick film portion 6E is greater than the thickness of the thin film portion 40. The outer thick film portions 64, 65, and 66 are disposed at equal intervals in the circumferential direction about the central axis C1.

[0063] The outer thick membrane portion 6E is disposed at a position closer to the base end portion 30P than the central position Pc. The inner diameter Ri(2) of the portion of the expanding portion 3B closer to the base end portion 30P than the central position Pc is the same in the outer thick membrane portion 6E and the thin membrane portion 40. Therefore, the inner surface 301 of this portion is smooth without unevenness. On the other hand, the outer diameter Ro(n) of the portion of the expanding portion 3B closer to the base end portion 30P than the central position Pc is different between the outer thick membrane portion 6E and the thin membrane portion 40. The outer diameter Ro(2) of the outer thick membrane portion 6E is larger than the outer diameter Ro(1) in the thin membrane portion 40. Therefore, the outer surface 302 of this portion protrudes outward in the outer thick membrane portion 6E. Hereinafter, this portion is referred to as the "protruding portion 600". The outer thick membrane portion 6E extends along the extension direction between the central position Pc and the base end portion 30P of the expanding portion 3B.

[0064] The thickness of the outer thick membrane portion 6E is uniform from the central position Pc to the base end 30P. Therefore, the outer diameter Ro(2) of the outer thick membrane portion 6E is uniform from the central position Pc to the base end 30P. In other words, the outward protrusion amount of the protrusion 600 formed on the outer surface 302 of the outer thick membrane portion 6E is uniform from the central position Pc to the base end 30P.

[0065] <Actions and Effects of the Fifth Embodiment> The balloon 3 of the balloon catheter 1E has an inner thick membrane portion 4E at a position closer to the tip 30D than the central position Pc, and an outer thick membrane portion 6E at a position closer to the base end 30P than the central position Pc. The outer thick membrane portion 6E is not provided at a position closer to the tip 30D of the expansion portion 3B of the balloon 3. Therefore, compared with the case where the outer thick membrane portion 6E is provided over the entire area of ​​the expansion portion 3B in the extension direction, the balloon 3 is less likely to be held in a fully extended state in the extension direction. Therefore, for example, even if the outer thick membrane portion 6E is caught by the stent at the stage of inserting the balloon 3 into a blood vessel in which a stent is placed, the balloon 3 can be prevented from being held in a fully extended state in the extension direction. Therefore, the balloon catheter 1E can prevent unnecessary force from acting on the stent from the balloon 3. Furthermore, the balloon catheter 1E can cause the outer thick membrane portion 6E to act on a lesion in the blood vessel when the balloon 3 is expanded.

[0066] <Special Notes on the Fifth Embodiment> The boundary between the inner thick membrane portion 4E and the outer thick membrane portion 6E is not limited to the center position Pc. For example, the boundary between the inner thick membrane portion 4E and the outer thick membrane portion 6E may be located at the position of the equal dividing line close to the tip end portion 30D among two equal dividing lines that divide the expansion portion 3B into three equal parts in the extension direction. Also, for example, the boundary between the inner thick membrane portion 4E and the outer thick membrane portion 6E may be located at the position of the equal dividing line close to the base end portion 30P among two equal dividing lines that divide the expansion portion 3B into three equal parts in the extension direction.

[0067] The inner thick membrane portion 4E may also be provided on the tip connecting portion 3A. In this case, the inner thick membrane portion 4E may extend along the extension direction between a portion of the tip connecting portion 3A that connects to the tip portion 30D of the expanding portion 3B and the tip portion 3D. The outer thick membrane portion 6E may also be provided on the base end connecting portion 3C. In this case, the outer thick membrane portion 6E may extend along the extension direction between a portion of the base end connecting portion 3C that connects to the base end portion 30P of the expanding portion 3B and the base end portion 3P.

[0068] The thickness of the inner thick membrane portion 4E and the outer thick membrane portion 6E may not be uniform in the stretching direction. For example, the thickness of each of the inner thick membrane portion 4E and the outer thick membrane portion 6E may be gradually reduced toward the center position Pc. The thickness of the inner thick membrane portion 4E may be gradually reduced toward the tip portion 30D. The thickness of the outer thick membrane portion 6E may be gradually reduced toward the base end portion 30P.

[0069] The inner surface 301 of the inflatable portion 3B may protrude inward at the outer thick membrane portion 6E. That is, at the outer thick membrane portion 6E, the outer surface 302 may protrude outward and the inner surface 301 may protrude inward.

[0070] <Sixth embodiment (balloon catheter 1F)> The balloon catheter 1F will be described with reference to Fig. 6. The balloon catheter 1F differs from the balloon catheter 1A in that a slit 7A is provided in the inner thick membrane portion 4A.

[0071] In the balloon catheter 1F, slits 71, 72, 73, and 74 (hereinafter, referred to as "slit 7A" when not distinguishing between them) are provided in each of the inner thick membrane parts 41 to 43. The slits 7A are cuts or notches provided in the protruding part 300 of the inner thick membrane part 4A. The slits 7A have a pair of inner walls 701 facing each other in the extension direction. The pair of inner walls 701 are connected at the deepest part (hereinafter, referred to as "bottom part 700"). When the slits 7A are cuts, the pair of inner walls 701 contact each other. When the slits 7A are notches, the pair of inner walls 701 are separated in the extension direction. When the slits 7A are notches, the distance between the pair of inner walls 701 in the extension direction becomes smaller as the depth of the slits 7A becomes deeper. In FIG. 6, the slits 7A are notches.

[0072] The slits 71, 72, 73, and 74 are arranged in this order in the stretching direction. The slit 71 is closest to the tip 30D of the expansion portion 3B of the balloon 3. The slit 74 is closest to the base end 30P of the expansion portion 3B of the balloon 3. The distance between the slits 71 and 72 in the stretching direction is denoted as s1. The distance between the slits 72 and 73 in the stretching direction is denoted as s2. The distance between the slits 73 and 74 in the stretching direction is denoted as s3. The distance s2 is larger than the distance s1, and the distance s3 is larger than the distance s2. In other words, the distance s between the slits 71 to 74 in the stretching direction becomes narrower as they approach the tip 30D of the expansion portion 3B of the balloon 3.

[0073] The depth of slit 71 is denoted as d1. The depth of slit 72 is denoted as d2. The depth of slit 73 is denoted as d3. The depth of slit 74 is denoted as d4. The depth d of slit 7A corresponds to the radial length from the inner surface 301 to the bottom 700 of the balloon 3. The depth d2 is smaller than the depth d1. The depth d3 is smaller than the depth d2. The depth d4 is smaller than the depth d3. In other words, the depth d of each of the slits 71 to 74 becomes deeper as it approaches the tip portion 30D of the expansion portion 3B of the balloon 3.

[0074] <Actions and Effects of the Sixth Embodiment> In the balloon catheter 1F, the inner thick membrane portion 4A can be bent by the slits 7A, so that the balloon 3 can be deformed well even in a tortuous blood vessel. Therefore, the balloon catheter 1F can make the balloon 3 follow the blood vessel well.

[0075] The distance s between the slits 71-74 in the extension direction becomes narrower as it approaches the tip 30D of the expansion section 3B. Here, the balloon 3 is more easily bent at the tip 30D where the distance s between the slits 71-74 is narrower. In this case, when the balloon 3 advances toward a meandering blood vessel or the like, the balloon 3 is more easily able to follow the blood vessel. Therefore, the user can make the balloon 3 reach the target site appropriately. On the other hand, the balloon 3 has greater rigidity at the base end 30P where the distance s between the slits 71-74 is wider. In this case, the stress that the balloon 3 applies to the lesion of the blood vessel can be increased, so that the efficiency of treatment by the expansion of the balloon 3 can be improved.

[0076] The depth d of each of the slits 71 to 74 becomes deeper as it approaches the tip 30D. Here, the balloon 3 becomes easier to bend as the tip 30D has a deeper depth d of the slits 71 to 74. In this case, when the balloon 3 advances toward a meandering blood vessel or the like, the balloon 3 becomes easier to follow the blood vessel. Therefore, the user can make the balloon 3 properly reach the target site. On the other hand, the balloon 3 becomes more rigid as it approaches the base end 30P where the depth d of the slits 71 to 74 is shallower. In this case, the stress that the balloon 3 applies to the lesion of the blood vessel can be increased, so that the efficiency of treatment by the expansion of the balloon 3 can be improved.

[0077] <Special Notes on the Sixth Embodiment> The number of slits 7A is not limited to the above embodiment, and may be 1 to 3, or 5 or more. A different number of slits 7A may be provided for each of the inner thick membrane portions 41 to 43. The positions of the slits 71 to 74 in the extension direction may be different for each of the inner thick membrane portions 41 to 43. The slits 71 to 74 having different depths d may be arranged at equal intervals in the extension direction. The depths d of the slits 71 to 74 arranged at different intervals s may be the same for all of the slits 71 to 74. The slits 71 to 74 having the same depth d may be arranged at equal intervals in the extension direction.

[0078] <Seventh embodiment (balloon catheter 1G)> A balloon catheter 1G will be described with reference to Fig. 7. The balloon catheter 1G differs from the balloon catheter 1C (see Fig. 3) in that a slit 7B is provided in the annular inner thick membrane portion 4C.

[0079] Slits 76A, 76B, and 76C are provided in the inner thick membrane portion 51 of the inflatable portion 3B. Slits 77A, 77B, and 77C are provided in the inner thick membrane portion 52. Slits 78A, 78B, and 78C are provided in the inner thick membrane portion 53. Slits 79A, 79B, and 79C are provided in the inner thick membrane portion 54. When the slits 76A to 76C, 77A to 77C, 78A to 78C, and 79A to 79C are not distinguished from one another, they are referred to as "slit 7B."

[0080] The slits 76A to 76C, the slits 77A to 77C, the slits 78A to 78C, and the slits 79A to 79C are arranged at equal intervals in the circumferential direction centered on the central axis C1. The circumferential positions of the slits 76A, 77A, 78A, and 79A are aligned with each other. The circumferential positions of the slits 76B, 77B, 78B, and 79B are aligned with each other. The circumferential positions of the slits 76C, 77C, 78C, and 79C are aligned with each other. Therefore, when the slit 7B is viewed from the extension direction, the positions of the slits 76A, 77A, 78A, and 79A overlap with each other, the positions of the slits 76B, 77B, 78B, and 79B overlap with each other, and the positions of the slits 76C, 77C, 78C, and 79C overlap with each other.

[0081] <Actions and Effects of the Seventh Embodiment> The balloon catheter 1G can bend the annular inner thick membrane portion 4C by the slits 7B, and can therefore be deformed well even in a tortuous blood vessel. This allows the balloon 3 to conform well to the blood vessel.

[0082] When the balloon 3 is viewed from the stretching direction, the positions of the slits 76A, 77A, 78A, and 79A overlap with each other, the positions of the slits 76B, 77B, 78B, and 79B overlap with each other, and the positions of the slits 76C, 77C, 78C, and 79C overlap with each other. Therefore, in the balloon catheter 1G, the portion in which the slit 7B is provided in the circumferential direction of the balloon 3 can be made a highly flexible portion, and the portion in which the slit 7B is not provided can be made a less flexible portion. In this case, by bending the balloon 3 at the highly flexible portion, the balloon 3 can easily follow the blood vessel when the balloon 3 enters a meandering blood vessel or the like. Therefore, the user can make the balloon 3 reach the desired site appropriately.

[0083] <Special Notes on the Seventh Embodiment> The number and positions of the slits 7B provided in each of the inner thick membrane portions 51-54 may be different from each other. Slits 7B may not be provided in some of the inner thick membrane portions 51-54 (for example, the inner thick membrane portion 54 closest to the base end portion 3P). All of the slits 7B may not overlap. For example, only the positions of the slits 76A, 77A, 78A, and 79A may overlap with each other, and the positions of the slits 76B, 77B, 78B, and 79B and the slits 76C, 77C, 78C, and 79C may not overlap.

[0084] <Other> The balloon 3 is an example of a "catheter balloon" of the present invention. The distal end 30D is an example of a "first distal end" of the present invention. The proximal end 30P is an example of a "first proximal end" of the present invention. The distal end 3D is an example of a "second distal end" of the present invention. The proximal end 3P is an example of a "second proximal end" of the present invention.

Claims

1. An expansion portion having a cylindrical shape extending in the extension direction; a tip connecting portion that extends from a first tip portion, which is an end portion on one side in the extension direction of the expansion portion, to a side opposite the expansion portion, and has an end portion connected to the expansion portion and has a diameter larger than a diameter of a second tip portion, which is an end portion opposite the end portion connected to the expansion portion; a base end connecting portion that extends from a first base end that is the other end of the expansion portion in the extension direction to a side opposite the expansion portion, and has an end connected to the expansion portion and has a diameter larger than a diameter of a second base end that is the end opposite the end connected to the expansion portion; A catheter balloon comprising: The inner thick portion and the thin portion are made of the same material and have different thicknesses, the inner thick portion has a greater thickness than the thin portion, an inner surface of the inner thick film portion protrudes radially inwardly about a central axis extending in the extension direction through a center of the expansion portion, further than an inner surface of the thin film portion; The outer surface of the inner thick film portion does not protrude outward in the radial direction relative to the outer surface of the thin film portion. A catheter balloon characterized by:

2. an outer diameter, which is the radial distance from the central axis to the outer surface, is the same for the thin film portion and the inner thick film portion; The inner diameter, which is the radial distance from the central axis to the inner surface, is smaller in the inner thick portion than in the thin portion.

2. The catheter balloon according to claim 1.

3. 3. The catheter balloon according to claim 1, wherein the inner thick membrane portion extends along the stretching direction.

4. The expansion portion is provided with the inner thick membrane portion. The catheter balloon according to claim 3, wherein the inner thick membrane portion extends from the first distal end portion to the first proximal end portion along the stretching direction.

5. The expansion portion is provided with an outer thick membrane portion having a thickness greater than that of the thin membrane portion, and the inner thick membrane portion, The inner diameter of the thin film portion is the same as that of the outer thick film portion, the outer diameter of the outer thick portion is larger than that of the thin portion; the inner thick film portion and the outer thick film portion extend along the extension direction and are aligned in the extension direction, The inner thick portion is closer to the first distal end portion than the outer thick portion, and the outer thick portion is closer to the first proximal end portion than the inner thick portion.

3. The catheter balloon according to claim 2.

6. The inner thick membrane portion is provided at the expansion portion, the tip connecting portion, and the base connecting portion, 6. The catheter balloon according to claim 1, wherein the inner thick membrane portion extends from the second distal end portion to the second proximal end portion along the stretching direction.

7. a thickness of the inner thick film portion of the tip connecting portion becomes thinner from a portion connected to the first tip portion of the expansion portion toward the second tip portion, The thickness of the inner thick membrane portion of the base end connecting portion becomes thinner from the portion connecting to the first base end of the inflatable portion toward the second base end.

7. The catheter balloon according to claim 6.

8. 8. The catheter balloon according to claim 1, wherein the inner thick membrane portion is provided with at least one slit.

9. A plurality of slits are provided arranged in the stretching direction, 9. The catheter balloon according to claim 8, wherein the intervals between the plurality of slits in the stretching direction become narrower as the slits approach the second tip portion.

10. A plurality of slits are provided arranged in the stretching direction, 10. The catheter balloon according to claim 8, wherein the depth of each of the plurality of slits increases as the slit approaches the second tip portion.

11. 2. The catheter balloon according to claim 1, wherein the inner thick membrane portion is annular and extends in a circumferential direction about the central axis.

12. 2. The catheter balloon according to claim 1, wherein the inner thick membrane portion has a spiral shape extending in a circumferential direction centered on the central axis and is provided between the first distal end portion and the first proximal end portion.

13. The catheter balloon according to claim 12, wherein the inner thick membrane portion is provided across the second distal end portion and the second proximal end portion.

14. 14. The catheter balloon according to claim 11, wherein the inner thick membrane portion is provided with at least one slit.

15. A plurality of slits are provided in the inner thick membrane portion, the slits being arranged in a direction in which the inner thick membrane portion extends.

15. The catheter balloon according to claim 14, wherein each of the plurality of slits is disposed at a position overlapping at least one of the other slits when viewed from the stretching direction.

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