Balloon catheter

Abstract

The balloon catheter (1A) has a catheter shaft (2), a balloon (3), and protrusions (4A, 4B). The balloon (3) has an expansion portion (3B) and a portion extending from the tip portion (30D) of the two ends of the expansion portion (3B) to the opposite side of the expansion portion (3B). The diameter of the end connected to the expansion portion (3B) is larger than the diameter of the tip portion (3D) on the opposite side, and the tip connecting portion (3A) connected to the catheter shaft (2) at the tip portion (3D). The protrusions (4A, 4B) protrude outward in the radial direction with respect to the central axis (C1) of the catheter shaft (2). The protrusion (4A) is provided on the tip connecting portion (3A). The protrusion (4B) is provided on the tip extension installation portion (220) of the inner tube (22). The tip connecting portion (3A) has at least an area between the protrusion (4A) and the tip portion (30D) that has a protrusion amount smaller than the protrusion amount of the protrusion (4A).

Description

Technology Field

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

[0002] Patent Document 1 discloses a balloon catheter having a linear protrusion provided on the balloon. The linear protrusion is provided across the entire axial direction of the balloon, extending across the base-side cone region, the straight region, and the tip-side cone region of the balloon. The linear protrusion protrudes outward from the outer surface of the balloon. Prior art literature

[0003] International Publication No. 2020 / 012850 The problem to be solved

[0004] When a balloon is inserted into a blood vessel, there is a problem in that the linear protrusion provided in the cone area at the tip may get caught on the inner wall of the blood vessel, thereby reducing the balloon's ability to pass through.

[0005] The objective of the present invention is to provide a balloon catheter capable of ensuring good passage of the balloon even when a protrusion is provided at the tip of the balloon. means of solving the problem

[0006] A balloon catheter according to the present invention comprises: a catheter shaft extending in an elongation direction over a first base portion and a first tip portion; a balloon connected to a position on the catheter shaft where the distance to the first tip portion is shorter than the distance to the first base portion; an expansion portion having a tubular shape extending in the elongation direction; a portion extending opposite to the expansion portion from a second tip portion, which is the end portion closest to the first tip portion among the two ends of the expansion portion in the elongation direction, wherein the diameter of the end portion connected to the expansion portion is larger than the diameter of the third tip portion, which is the end portion opposite to the end portion connected to the expansion portion, and the balloon having a tip connecting portion connected to the catheter shaft at the third tip portion; a protrusion protruding outward in the diameter direction with respect to the central axis of the catheter shaft; a first protrusion provided at the tip connecting portion of the balloon; and a portion between the third tip portion and the first tip portion of the balloon in the elongation direction. The protrusion is provided with at least one of the second protrusions provided in the tip extension installation part, and the tip connecting part is characterized by having at least an area between the end of the protrusion closest to the second tip and the second tip, wherein the protrusion has a protrusion amount smaller than the protrusion amount of the protrusion.

[0007] The balloon catheter can make the area where the protrusion is provided at the tip connection smaller than when the protrusion is provided over the entire tip connection. Because of this, the balloon catheter can ensure good passage of the balloon within the blood vessel even when the protrusion is provided.

[0008] In the present invention, the protrusion may include the first protrusion. In this case, the balloon catheter may apply the first protrusion to the lesion during the process of expanding the lesion within the blood vessel by repeatedly inflating and deflating the balloon. In this case, since the balloon catheter can advance the balloon little by little toward a lesion with a small lumen, the lesion can be effectively expanded.

[0009] In the present invention, the first protrusion comprises a first apex that protrudes most outwardly in the diameter direction, a first tip gradient extending toward the first apex from an end on the side adjacent to the third tip, and a first base gradient extending toward the first apex from an end on the side adjacent to the second tip. The angle of the first base gradient relative to the tip connection may be greater than the angle of the first tip gradient relative to the tip connection. In this case, the balloon catheter can suppress the resistance received from the lesion site during the advancement of the balloon. Therefore, the balloon catheter can reduce the retraction of the balloon caused by the resistance received from the lesion site during the process of the balloon advancing.

[0010] In the present invention, the first protrusion may be provided in a portion including the third tip. In this case, when the balloon catheter enters a lesion within a blood vessel and expands the lesion by repeatedly inflating and deflating the balloon in this state, the balloon may be repelled in the direction opposite to the direction of travel by the first protrusion of the third tip.

[0011] In the present invention, the protrusion may further include a third protrusion provided in the expansion portion of the balloon, and may also have an inner protrusion that extends between the first protrusion and the third protrusion and protrudes inward in the diameter direction from the inner surface of the tip connecting portion. In this case, the balloon catheter can make the rigidity of the portion of the balloon where the inner protrusion is provided equal to the rigidity of the portion of the balloon where the first protrusion is provided. Therefore, when the balloon is inflated, the inner protrusion can suppress the first protrusion from being pushed back in the direction toward the central axis due to stress from the lesion. Additionally, since the inner protrusion protrudes inward from the inner surface of the tip connecting portion, it can suppress the decrease in the balloon's passability.

[0012] In the present invention, the first protrusion may have an annular shape extending in a peripheral direction around the central axis. The balloon catheter can apply the first protrusion to the lesion site over a wide range in the peripheral direction at the tip connection. Accordingly, the balloon catheter can prevent the balloon from moving in the elongation direction while the first protrusion is applied to the lesion site during balloon inflation.

[0013] In the present invention, the first protrusion may have a spiral shape extending in a peripheral direction around the central axis. The balloon catheter can apply the first protrusion to the lesion site over a wide range in the peripheral and elongation directions at the tip connection. Accordingly, the balloon catheter can prevent the balloon from moving in the elongation direction while the first protrusion is applied to the lesion site during balloon inflation.

[0014] In the present invention, the tip connecting portion has a plurality of inclined portions, and the plurality of inclined portions each include at least two inclined portions in which the angle of inclination formed between the central axis and the direction extending from the second tip portion side toward the third tip portion side along each portion is different from each other, and the first protrusion may be provided on the inclined portion having the smallest angle of inclination among the plurality of inclined portions. In this case, the direction of movement of the first protrusion, which moves during balloon inflation, can be made close to the diameter direction. In this case, the balloon catheter can appropriately act the first protrusion toward the lesion site.

[0015] In the present invention, the protrusion may include the second protrusion. In this case, the balloon catheter can apply the second protrusion of the tip extension mounting portion to the lesion during the process of advancing the balloon within the blood vessel. In this case, the balloon catheter can advance the balloon even within a lesion with a small lumen. Additionally, when the balloon catheter expands the lesion within the blood vessel by repeatedly inflating and deflating the balloon, the balloon may be prevented from being pushed back in the direction opposite to the direction of advancement by the second protrusion of the tip extension mounting portion.

[0016] In the present invention, the second protrusion has a plurality of protrusions, and the protrusion amount of each of the plurality of protrusions may increase as it approaches the third tip. In this case, the balloon catheter can suppress the resistance received from the lesion site during the entry of the balloon. For this reason, the balloon catheter can reduce the balloon being pushed back in the direction opposite to the entry direction due to the resistance received from the lesion site during the process of the balloon entering the lesion site.

[0017] In the present invention, the second protrusion comprises a second vertex that protrudes most outwardly in the diameter direction, a second tip gradient extending toward the second vertex from an end on the side adjacent to the first tip, and a second base gradient extending toward the second vertex from an end on the side adjacent to the third tip. The angle of the second base gradient relative to the tip extension installation part may be greater than the angle of the second tip gradient relative to the tip extension installation part. In this case, the balloon catheter can reduce the obstruction of the balloon's progression by the second protrusion getting caught in the blood vessel when advancing the balloon within the blood vessel.

[0018] In the present invention, the tip extension installation portion may have at least an area between the end closest to the first tip portion among the protrusions and the first tip portion, wherein the protrusion amount is smaller than the protrusion amount of the protrusion. In this case, the balloon catheter may make the size of the area where the protrusion is provided in the tip extension installation portion smaller than when the protrusion is provided over the entire tip extension installation portion. Therefore, the balloon catheter can ensure good passage of the balloon within the blood vessel even when the protrusion is provided. Brief explanation of the drawing

[0019] FIG. 1 is a side view of a balloon catheter (1A). FIG. 2 is a view of the balloon catheter (1A) from the tip side. FIG. 3a is a drawing for illustrating an example of use of a balloon catheter (1A). FIG. 3b is a drawing illustrating an example of use of a balloon catheter (1A). FIG. 3c is a drawing illustrating an example of use of a balloon catheter (1A). FIG. 3d is a drawing for illustrating an example of use of a balloon catheter (1A). FIG. 3e is a drawing for illustrating an example of use of a balloon catheter (1A). FIG. 4a is a drawing illustrating an example of use of a balloon catheter (1A). FIG. 4b is a drawing illustrating an example of use of a balloon catheter (1A). FIG. 4c is a drawing illustrating an example of use of a balloon catheter (1A). FIG. 4d is a drawing illustrating an example of use of a balloon catheter (1A). FIG. 4e is a drawing illustrating an example of use of a balloon catheter (1A). FIG. 5a is a drawing illustrating an example of use of a balloon catheter (1A). FIG. 5b is a drawing illustrating an example of use of a balloon catheter (1A). FIG. 5c is a drawing illustrating an example of use of a balloon catheter (1A). FIG. 5d is a drawing illustrating an example of use of a balloon catheter (1A). FIG. 6 is an enlarged view of the vicinity of the tip connection (3A) of the balloon catheter (1B). FIG. 7 is an enlarged view of the vicinity of the tip connection (3A) of the balloon catheter (1C). FIG. 8 is an enlarged view of the vicinity of the tip connection (3A) of the balloon catheter (1D). FIG. 9 is an enlarged view of the vicinity of the tip connection (3A) of the balloon catheter (1E). FIG. 10 is a side view of the balloon catheter (1F) and a cross-sectional view of the line AA in the direction of the arrow. Figure 11 is a drawing showing a modified example of a balloon catheter (1F). FIG. 12a is a drawing showing a modified example of the protrusions (41G, 42G). FIG. 12b is a drawing showing a modified example of the protrusions (41G, 42G). FIG. 12c is a drawing showing a modified example of the protrusions (41G, 42G). FIG. 13a is a drawing showing a protrusion (46G). FIG. 13b is a drawing showing a protrusion (47G). FIG. 13c is a drawing showing a protrusion (48G). FIG. 14 is an enlarged view of the vicinity of the tip connection (3A) of the balloon catheter (1G). FIG. 15 is an enlarged cross-sectional view of the vicinity of the tip connection (3A) of the balloon catheter (1H). FIG. 16a is a cross-sectional view showing a cover tube (7B). FIG. 16b is a cross-sectional view showing the cover tube (7C). FIG. 16c is a cross-sectional view showing the cover tube (7D). Specific details for implementing the invention

[0020] An embodiment of the balloon catheter (1) according to the present invention (balloon catheter (1A to 1H)) will be described with reference to the drawings. The drawings referenced are used to explain the technical features that can be adopted by the present invention. The configuration of the device described is not intended to be limited thereto and is merely an example for explanation. The balloon catheter (1) can expand a stenotic lesion formed in a blood vessel by means of the balloon (3) or act on the blood vessel using the protrusion (4) (protrusion (4A to 4E, 4G, 4I)) described later.

[0021] <First embodiment (balloon catheter (1A))>

[0022] Referring to FIGS. 1 and 2, a balloon catheter (1A) is described. The balloon catheter (1A) has a catheter shaft (2), a balloon (3), and protrusions (4A, 4B).

[0023] <Catheter shaft (2)>

[0024] The catheter shaft (2) has a tubular shape. A balloon (3) is connected near one end of the catheter shaft (2). A hub (not shown) is connected to the other end of the catheter shaft (2). The hub can supply compressed fluid to the balloon (3) through the catheter shaft (2).

[0025] One of the two ends of the catheter shaft (2) is called the "tip side." The other of the two ends of the catheter shaft (2) is called the "base side." The direction extending along the catheter shaft (2) is called the "extension direction." The axis extending in the extension direction through the center of the catheter shaft (2) is called the "center axis C1." In the cross-section (hereinafter simply referred to as the "cross-section") obtained by cutting in a plane perpendicular to the center axis C1, the side closer to the center axis C1 in the radial direction centered on the center axis C1 is called the "inner side," and the side spaced apart from the center axis C1 is called the "outer side."

[0026] The catheter shaft (2) has an outer tube (21) and an inner tube (22). The outer tube (21) and the inner tube (22) each have flexibility. The inner diameter of the outer tube (21) is larger than the outer diameter of the inner tube (22). The inner tube (22) is positioned in the lumen of the outer tube (21), except for a predetermined portion at the tip. The predetermined portion at the tip of the inner tube (22) protrudes toward the tip from the tip end of the outer tube (21) (hereinafter referred to as the "tip portion (211)"). The tip end of the inner tube (22) (hereinafter referred to as the "tip portion (221)") is positioned further toward the tip than the tip portion (211) of the outer tube (21). Hereinafter, the predetermined portion at the tip of the inner tube (22) is referred to as the "protruding portion (225)." The end of the outer tube (21) on the base side is called the "base portion (212)." The end of the inner tube (22) on the base side is called the "base portion (222)." At least the base portion (212) of the outer tube (21) is connected to a hub. The materials of the outer tube (21) and the inner tube (22) are not particularly limited, but as an example, a polyamide resin is used.

[0027] In the lumen of the outer tube (21), compressed fluid supplied from the hub flows through the space other than the lumen of the inner tube (22). A guide wire, not shown, is inserted and penetrates through the lumen of the inner tube (22).

[0028] Balloon (3)

[0029] The balloon (3) can be deformed between a contracted state and an expanded state by changing its internal pressure depending on whether or not a compressed fluid is supplied by a hub not shown. FIG. 1 shows the balloon (3) in an expanded state.

[0030] The balloon (3) has a tip end (hereinafter referred to as "tip end (3D)") connected by heat welding to a portion of the inner tube (22) protruding part (225) that is closer to the base end (221) than to the tip end (221). Hereinafter, the portion of the inner tube (22) protruding part (225) between the portion where the tip end (3D) of the balloon (3) is connected and the tip end (221) is referred to as the "tip extension installation portion (220)". Additionally, the balloon (3) has a base end (hereinafter referred to as "base end (3P)") connected by heat welding to the vicinity of the tip end (211) of the outer tube (21). The distance between the tip (3D) of the balloon (3) and the tip (221) of the inner tube (22) is shorter than the distance between the base (3P) of the balloon (3) and the base (222) of the inner tube (22). The balloon (3) covers the protruding part (225) of the inner tube (22) from the outside. The material of the balloon (3) is not particularly limited, but as an example, a polyamide resin is used.

[0031] In the balloon (3), a tip connecting portion (3A), an expansion portion (3B), and a base connecting portion (3C) are defined. The tip connecting portion (3A) is an area that extends outward from the tip portion (3D) toward the base portion (3P) while expanding in the balloon (3) in the expanded state. The base connecting portion (3C) is an area that extends outward from the base portion (3P) toward the tip portion (3D) while expanding in the balloon (3) in the expanded state. The expansion portion (3B) is an area sandwiched between the tip connecting portion (3A) and the base connecting portion (3C) in the balloon (3) in the expanded state, and its diameter becomes approximately the same over the elongation direction. In the expanded state, the expansion portion (3B) takes the shape of a tube extending in the elongation direction. Among the expansion portion (3B), the side adjacent to the tip portion (221) of the inner tube (22) of the catheter shaft (2), i.e., the tip portion, is called the "tip portion (30D)." Among the expansion portion (3B), the side adjacent to the base portion (222) of the inner tube (22) of the catheter shaft (2), i.e., the base portion, is called the "base portion (30P)."

[0032] The tip connecting portion (3A) extends toward the tip portion (3D) from the end connected to the tip portion (30D) of the expansion portion (3B). The diameter of the cross-section of the tip connecting portion (3A) is largest at the end connected to the tip portion (30D) of the expansion portion (3B) and becomes smallest at the tip portion (3D). The base connecting portion (3C) extends toward the base portion (3P) from the end connected to the base portion (30P) of the expansion portion (3B). The diameter of the cross-section of the base connecting portion (3C) is largest at the end connected to the base portion (30P) of the expansion portion (3B) and becomes smallest at the base portion (3P).

[0033] <Protrusion (4A)>

[0034] The protrusion (4A) is provided on the outer surface of the leading edge connecting part (3A) of the balloon (3) and protrudes outward. The protrusion (4A) has protrusions (41A, 42A). The protrusions (41A, 42A) face each other with the central axis C1 in between. Each of the protrusions (41A, 42A) has a conical shape. The apex (410) of the protrusions (41A, 42A) protrudes outward the most in the protrusions (41A, 42A). The bottom of the protrusions (41A, 42A) is connected to the outer surface of the leading edge connecting part (3A) of the balloon (3). The protrusions (41A, 42A) have the same shape. The shortest distance between the bottom surface of each protrusion (41A, 42A) and the apex (410) corresponds to the amount of protrusion of the protrusion (4A). Hereinafter, the shape of the protrusion (4A) is explained by exemplifying the protrusion (41A).

[0035] The portion of the bottom of the protrusion (41A) closest to the front portion (3D) of the front connecting portion (3A) is called the front portion (415). The portion of the side of the protrusion (41A) corresponding to the parent line connecting the apex (410) and the front portion (415) is called the "front slope portion (411)." The front slope portion (411) extends along the side of the protrusion (41A) from the front portion (415) toward the apex (410). The portion of the bottom of the protrusion (41A) closest to the front portion (30D) of the expansion portion (3B) is called the base portion (416). The portion of the side of the protrusion (41A) corresponding to the parent line connecting the apex (410) and the base portion (416) is called the "base slope portion (412)." The base slope portion (412) extends along the side of the protrusion (41A) from the base portion (416) toward the apex (410). In this case, the angle θ12 of the base slope portion (412) relative to the tip connection portion (3A) is greater than the angle θ11 of the tip slope portion (411) relative to the tip connection portion (3A) (θ11 < θ12).

[0036] Each base portion (416) of the protrusions (41A, 42A) is spaced apart toward the front portion (30D) of the expansion portion (3B) of the balloon (3). Because of this, the front portion connecting portion (3A) of the balloon (3) includes an area W1 where the protrusion (4A) is not provided between the portion connected to the front portion (30D) of the expansion portion (3B) in the elongation direction and the base portion (416) of the protrusion (4A). Each base portion (415) of the protrusions (41A, 42A) is spaced apart toward the front portion (3D) of the front portion connecting portion (3A) of the balloon (3). For this reason, the leading edge connecting portion (3A) of the balloon (3) includes an area W2 in which the protrusion (4A) is not provided between the leading edge portion (3D) and the leading edge portion (415) of the protrusion (4A) in the elongation direction.

[0037] <Protrusion (4B)>

[0038] The protrusion (4B) is provided on the outer surface of the tip extension installation part (220) of the inner tube (22) and protrudes outward. The protrusion (4B) has protrusions (41B, 42B). The protrusions (41B, 42B) face each other with the central axis C1 in between. Each of the protrusions (41B, 42B) has a conical shape. The apex (420) of the protrusions (41B, 42B) protrudes outward the most in the protrusions (41B, 42B). The bottom of the protrusions (41B, 42B) is connected to the outer surface of the tip extension installation part (220). The protrusions (41B, 42B) have the same shape. The amount of protrusion of the protrusion (4B) is smaller than the amount of protrusion of the protrusion (4A). Below, the shape of the protrusion (4B) will be explained by exemplifying the protrusion (41B).

[0039] The portion of the lower part of the protrusion (41B) closest to the tip portion (221) of the inner tube (22) is called the tip portion (425). The portion of the side of the protrusion (41B) corresponding to the main line connecting the apex (420) and the tip portion (425) is called the "tip slope portion (421)." The tip slope portion (421) extends along the side of the protrusion (41B) from the tip portion (425) toward the apex (420). The portion of the lower part of the protrusion (41B) closest to the tip portion (3D) of the tip connection portion (3A) of the balloon (3) is called the base portion (426). The portion of the side of the protrusion (41B) corresponding to the main line connecting the apex (420) and the base portion (426) is called the "base slope portion (422)." The base slope portion (422) extends along the side of the protrusion (41B) from the base portion (426) toward the apex (420). In this case, the angle θ22 of the base slope portion (422) relative to the tip extension installation portion (220) is greater than the angle θ21 of the tip slope portion (421) relative to the tip extension installation portion (220) (θ21 < θ22).

[0040] Each base portion (426) of the protrusions (41B, 42B) is spaced apart toward the front portion (3D) of the front portion connecting portion (3A) of the balloon (3). Because of this, the front portion extension installation portion (220) of the inner tube (22) includes an area W3 where the protrusion (4B) is not provided between the portion where the front portion (3D) of the front portion connecting portion (3A) of the balloon (3) is connected in the elongation direction and the base portion (426) of the protrusion (4B). Each base portion (425) of the protrusions (41B, 42B) is spaced apart toward the front portion (221) of the inner tube (22). For this reason, the tip extension installation part (220) of the inner tube (22) includes an area W4 in which the protrusion (4B) is not provided between the tip part (221) and the tip part (425) of the protrusion (4B) in the elongation direction.

[0041] <Usage Example>

[0042] An example of the use of a balloon catheter (1A) is described. An example is given of a balloon catheter (1A) being used to expand a stenotic lesion (90A) that has occurred in a part of the inner wall of a blood vessel (9). The lumen of the stenotic lesion (90A) is very narrow, and the diameter of the lumen is smaller than the diameter of the balloon (3) in a contracted state.

[0043] A guide wire G is inserted and penetrated into a blood vessel (9). A balloon catheter (1A) with the balloon (3) in a deflated state is prepared. As shown in FIG. 3a, at least the portion of the balloon catheter (1A) containing the balloon (3) is placed inside the blood vessel (9). A guide wire G is inserted and penetrated into the inner tube (22) of the balloon catheter (1A).

[0044] Next, as the base of the balloon catheter (1A) is manipulated, the balloon catheter (1A) is pressed into the blood vessel (9) along the guide wire G. The balloon catheter (1A) moves distally within the blood vessel (9) toward the stenotic lesion (90A) with the balloon (3) positioned at the leading edge of the direction of movement. The tip connecting portion (3A) of the balloon (3) reaches the vicinity of the proximal end of the stenotic lesion (90A). As shown in FIG. 3b, only a portion of the tip connecting portion (3A) of the balloon (3) enters the proximal end of the lumen of the stenotic lesion (90A). After that, the movement of the balloon catheter (1A) toward the distal end is stopped.

[0045] Next, as shown in FIG. 3c, the supply of compressed fluid to the balloon (3) is initiated, and the balloon (3) becomes inflated. The protrusion (4A) provided on the tip connecting part (3A) penetrates into the inner wall of the stenotic lesion (90A). The balloon (3) expands the proximal end of the lumen of the stenotic lesion (90A) by means of the tip connecting part (3A). Furthermore, since the tip connecting part (3A) is expanded toward the proximal side, a force acting toward the proximal side acts from the stenotic lesion (90A) to the balloon (3) as the balloon (3) changes into an inflated state. However, because the protrusion (4A) penetrates into the stenotic lesion (90A), the movement of the balloon (3) toward the proximal side is inhibited. In addition, the protrusion (4B) catches on the lumen of the constricted lesion (90A), thereby preventing the balloon (3) from being pushed back toward the proximal side.

[0046] Next, as shown in FIG. 3d, the supplied compressed fluid is removed from the balloon (3), and the balloon (3) becomes deflated. Next, as shown in FIG. 3e, the balloon catheter (1A) moves distally by manipulating the base. The tip connection (3A) of the balloon (3) enters from the expanded proximal end of the stenotic lesion (90A) toward a deeper part of the lumen. After that, the movement of the balloon catheter (1A) stops.

[0047] Next, as shown in FIG. 4a, the supply of compressed fluid to the balloon (3) is initiated, and the balloon (3) becomes inflated. The protrusion (4A) provided on the tip connecting part (3A) penetrates into the inner wall of the stenotic lesion (90A). The balloon (3) expands the portion of the stenotic lesion (90A) that is distal to the expanded portion shown in FIG. 3c and FIG. 3d by the tip connecting part (3A). Additionally, the balloon (3) expands the portion of the stenotic lesion (90A) that is expanded in FIG. 3c and FIG. 3d by the expansion part (3B). As a result, a more extensive portion of the lumen of the stenotic lesion (90A) is expanded by the balloon (3). Additionally, the protrusion (4A) penetrates into the stenotic lesion (90A), and the protrusion (4B) is caught in the lumen of the stenotic lesion (90A). Because of this, as the balloon (3) changes to an inflated state, even if a force acting on the balloon (3) in a direction toward the proximal side is applied, the movement of the balloon (3) toward the proximal side is inhibited.

[0048] Next, as shown in FIG. 4b, the supplied compressed fluid is removed from the balloon (3), and the balloon (3) becomes contracted.

[0049] The same procedure as above is repeated (Figs. 4c, 4d, 4e). As a result, the balloon (3) of the balloon catheter (1A) moves the lumen of the stenotic lesion (90A) toward the distal side little by little. As shown in Figs. 5a, 5b, and 5c, the lumen of the stenotic lesion (90A) gradually expands from near the proximal end toward the distal side. Finally, as shown in Fig. 5d, the lumen of the stenotic lesion (90A) is expanded throughout by the balloon (3).

[0050] After that, the base of the balloon catheter (1A) is manipulated so that the balloon catheter (1A) moves proximally. The procedure is completed when the balloon catheter (1A) is withdrawn out of the blood vessel (9).

[0051] <Operation and Effect of the First Embodiment>

[0052] The balloon catheter (1A) can expand a narrowed lesion (90A) with a small lumen by repeatedly changing the balloon (3) between an inflated state and a contracted state and advancing it little by little towards the distal side. Here, in the balloon catheter (1A), a protrusion (4A) is provided on the tip connecting part (3A) of the balloon (3), and a protrusion (4B) is provided on the tip extension installation part (220) of the inner tube (22). The protrusions (4A, 4B) prevent the balloon (3) from moving proximally even when the balloon (3) receives a force directed proximally from the narrowed lesion (90A) during the expansion of the balloon (3). Because of this, the balloon catheter (1A) can properly expand a narrowed lesion (90A) with a small lumen by performing the action of moving the balloon (3) little by little towards the distal side while repeatedly changing the balloon (3) between an inflated state and a contracted state.

[0053] The tip connection part (3A) of the balloon (3) includes areas W1 and W2 where no protrusion (4A) is provided. Because of this, the size of the area where the protrusion (4A) is provided within the tip connection part (3A) is smaller than when the protrusion (4A) is provided throughout the entire lengthening direction of the tip connection part (3A). Additionally, the tip extension installation part (220) of the inner tube (22) includes areas W3 and W4 where no protrusion (4B) is provided. Because of this, the size of the area where the protrusion (4B) is provided within the tip extension installation part (220) is smaller than when the protrusion (4B) is provided throughout the entire lengthening direction of the tip extension installation part (220). Accordingly, the balloon catheter (1A) can improve the passage of the balloon (3) within the blood vessel (9) compared to the case where protrusions (4A, 4B) are provided throughout the tip connection part (3A) and tip extension installation part (220).

[0054] The balloon catheter (1A) can cause the protrusion (4A) provided at the tip connection (3A) of the balloon (3) to penetrate into the stenotic lesion (90A) during the process of expanding the stenotic lesion (90A) within the blood vessel (9) by repeatedly expanding and contracting the balloon (3). In this case, even when the balloon (3) receives a force directed proximally from the stenotic lesion (90A) during the expansion of the balloon (3), the balloon (3) can be prevented from retracting proximally. Therefore, the balloon catheter (1A) can expand the stenotic lesion (90A) with a small lumen by advancing the balloon (3) little by little, thus allowing the stenotic lesion (90A) with a small lumen to be expanded efficiently.

[0055] In the protrusion (4A), the angle θ12 of the base slope (412) relative to the tip connection (3A) is greater than the angle θ11 of the tip slope (411) relative to the tip connection (3A). In this case, when the balloon (3) enters the lumen of the stenotic lesion (90A), the resistance force received by the protrusion (4A) from the stenotic lesion (90A) can be suppressed. Because of this, the balloon catheter (1A) can reduce the balloon (3) being pushed back proximally by the resistance force received from the stenotic lesion (90A) during the process of the balloon (3) entering the stenotic lesion (90A).

[0056] The protrusion (4B) provided on the tip extension mounting part (220) of the balloon (3) catches on the stenotic lesion (90A) when the balloon (3) moves in the direction of entry and the opposite direction within the blood vessel (9). Because of this, the balloon catheter (1A) can prevent the balloon (3) from being pushed back proximally by the protrusion (4B) of the tip extension mounting part (220) when the balloon (3) is expanded / contracted to expand the stenotic lesion (90A) within the blood vessel (9).

[0057] In the protrusion (4B), the angle θ22 of the base slope (422) relative to the tip extension installation part (220) is greater than the angle θ21 of the tip slope (421) relative to the tip extension installation part (220). In this case, the balloon catheter (1A) can reduce the obstruction of the balloon (3) advancing within the blood vessel (9) by the protrusion (4B) getting caught on the blood vessel (9).

[0058] <Special Features of the First Embodiment>

[0059] The shape, number, and arrangement of each protrusion of the protrusions (4A, 4B) are not limited to the above embodiments. For example, the number of each protrusion of the protrusions (4A, 4B) may be one or three or more. In addition, if the number of protrusions is three or more, the three or more protrusions may be arranged in a peripheral direction centered on the central axis C1. The shape of each protrusion of the protrusions (4A, 4B) may be a pyramid, a frustum, a truncated pyramid, etc., or a prism. In addition, if the shape of the protrusions (41A, 42A) of the protrusion (4A) is a triangular prism, one of the sides may be connected to the front connecting part (3A) of the balloon (3), the remaining two sides may form the front slope part (411) and the base slope part (412), and the intersection of the remaining two sides may form the vertex (410). Likewise, if the shape of the protrusions (41B, 42B) of the protrusion (4B) is a triangular prism, one of the sides may be connected to the tip extension installation part (220) of the inner tube (22), the other two sides may form the tip gradient part (421) and the base gradient part (422), and the intersection of the other two sides may form the vertex (420).

[0060] A plurality of protrusions of the protrusion (4A) may be arranged in an elongation direction along the tip connection (3A) of the balloon (3). For example, when viewing the balloon (3) from the tip side, a plurality of protrusions may be arranged along each of a plurality of virtual lines extending radially from the central axis C1. In this case, the protrusion amount of each of the plurality of protrusions does not have to be the same. For example, the protrusion amount of each of the plurality of protrusions may be determined according to the distance from the central axis C1.

[0061] A first connecting part may be provided to connect the protrusions (41A, 41B). A second connecting part may be provided to connect the protrusions (42A, 42B). The first connecting part and the second connecting part may protrude outwardly from the outer surface of the tip connecting part (3A) of the balloon (3) and the outer surface of the tip extension installation part (220) of the inner tube (22), respectively. That is, the protrusions (41A, 41B) and the protrusions (42A, 42B) may each be integrally formed to form a single protrusion.

[0062] The position of the elongation direction of each base portion (416) of the protrusions (41A, 42A) of the protrusion (4A) may coincide with the portion connected to the front portion (30D) of the expansion portion (3B) of the front connecting portion (3A). Alternatively, the position of the elongation direction of each front portion (415) of the protrusions (41A, 42A) of the protrusion (4A) may coincide with the front portion (3D) of the front connecting portion (3A).

[0063] The protrusions (41B, 42B) of the protrusion (4B) may each be provided extending from the tip portion (221) of the inner tube (22) in the tip extension installation portion (220) to the part where the tip portion (3D) of the tip connection portion (3A) is connected. The position of each tip portion (425) of the protrusions (41B, 42B) may coincide with the position of the tip portion (221) of the inner tube (22). The base portion (426) of each protrusion (41B, 42B) may coincide with the position of the tip portion (3D) of the tip connection portion (3A). That is, the protrusions (4B) may be provided throughout the entire lengthening direction of the tip extension installation portion (220) of the inner tube (22). In this case, the areas W3 and W4 in the leading edge extension installation part (220) of the inner tube (22) where the protrusion (4B) is not provided in the elongation direction may be omitted.

[0064] The balloon catheter (1A) may have only one of the protrusions (4A, 4B). For example, the balloon catheter (1A) may have only the protrusion (4A) and not the protrusion (4B). Or, the balloon catheter (1A) may have only the protrusion (4B) and not the protrusion (4A).

[0065] In the protrusion (4A), the angle θ11 of the tip slope portion (411) relative to the tip connection portion (3A) and the angle θ12 of the base slope portion (412) relative to the tip connection portion (3A) may be the same, or the angle θ11 may be greater than the angle θ12. Either angle θ11 or angle θ12 may be orthogonal to the tip connection portion (3A). In the protrusion (4B), the angle θ21 of the tip slope portion (421) relative to the tip extension installation portion (220) and the angle θ22 of the base slope portion (422) relative to the tip extension installation portion (220) may be the same, or the angle θ21 may be greater than the angle θ22. Either angle θ21 or angle θ22 may be orthogonal to the tip extension installation portion (220).

[0066] In the regions W1 and W2 of the leading edge connecting portion (3A) of the balloon (3), a first convex portion having a protrusion amount smaller than the protrusion amount of the protrusion (4A) may be provided. Additionally, in the regions W3 and W4 of the leading edge extension installation portion (220), a second convex portion having a protrusion amount smaller than the protrusion amount of the protrusion (4B) may be provided. The ratio of the protrusion amount of the first convex portion to the protrusion amount of the protrusion (4A) and the ratio of the protrusion amount of the second convex portion to the protrusion amount of the protrusion (4B) are not particularly limited, but as an example, they are 50% or less, more preferably 10% or less.

[0067] In the case where the balloon catheter (1A) has only a protrusion (4B) and a first convex portion is provided, the first convex portion may be provided over the entire area between the portion connected to the tip portion (30D) of the expansion portion (3B) of the balloon (3) and the tip portion (3D). Additionally, the protrusion amount of the first convex portion may be smaller than the protrusion amount of the protrusion (4B).

[0068] In the case where the balloon catheter (1A) has only a protrusion (4A) and a second convex portion is provided, the second convex portion may be provided over the entire area between the portion connected to the tip (3D) of the balloon (3) and the tip (221) of the tip extension installation portion (220). Additionally, the protrusion amount of the second convex portion may be smaller than the protrusion amount of the protrusion (4A).

[0069] <Second embodiment (balloon catheter (1B))>

[0070] Referring to FIG. 6, a balloon catheter (1B) will be described. The balloon catheter (1B) differs from the balloon catheter (1A) in that it does not have a protrusion (4B) and has a protrusion (4C) instead of a protrusion (4A). Hereinafter, the description of the balloon catheter (1B) that is identical to the balloon catheter (1A) will be omitted.

[0071] The protrusion (4C) has 41C and 42C having the same shape as the protrusions (41A, 41B) of the protrusion (4A). The protrusions (41C, 42C) are provided in the portion including the tip (3D) among the outer surface of the tip connecting portion (3A) of the balloon (3). In this case, a portion of the tip side of each protrusion (41C, 42C) is provided on the outer surface of the tip extension installation portion (220) of the inner tube (22), and a portion of the base side of each protrusion (41C, 42C) is provided on the outer surface of the tip connecting portion (3A) of the balloon (3). Additionally, each front end (415) of the protrusions (41C, 42C) is located on the front side of the front end (3D) of the front end connecting part (3A) of the balloon (3), and each base end (416) of the protrusions (41C, 42C) is located on the base side of the front end (3D) of the front end connecting part (3A) of the balloon (3).

[0072] <Action and Effect of the Second Embodiment>

[0073] With the balloon catheter (1B), the tip portion (3D) of the balloon (3) enters the stenotic lesion (90A) within the blood vessel (9), and the balloon (3) is inflated to expand the stenotic lesion (90A). In this case, even if the area of ​​the balloon catheter (1B) that enters the stenotic lesion (90A) is very small, the balloon (3) can be prevented from being pushed back in the direction of travel and the reverse direction by the protrusion (4C). Because of this, the balloon catheter (1B) can expand the stenotic lesion (90A) by repeatedly inflating and contracting the balloon (3), even when the stenotic lesion (90A) is hard and it is difficult to enter the tip portion (3A) of the balloon (3) in a contracted state into the lumen.

[0074] <Special details of the second embodiment>

[0075] In addition to the protrusion (4C), a protrusion (4A) according to the first embodiment may be provided on the tip connecting part (3A). Also, in addition to the protrusion (4C), a protrusion (4B) according to the first embodiment may be provided on the tip extension installation part (220).

[0076] <Third embodiment (balloon catheter (1C))>

[0077] Referring to FIG. 7, a balloon catheter (1C) will be described. The balloon catheter (1C) is different from the balloon catheter (1A) in that it does not have a protrusion (4B) and has a protrusion (4D) instead of a protrusion (4A). Hereinafter, the description of the balloon catheter (1C) that is identical to the balloon catheter (1A) will be omitted.

[0078] The protrusion (4D) has protrusions (41D, 42D, 43D). The protrusions (41D to 43D) are provided on the outer surface of the tip connecting part (3A) of the balloon (3) and protrude outward. Each of the protrusions (41D to 43D) has an annular shape extending in a peripheral direction around a central axis C1. The protrusions (41D, 42D, 43D) are arranged in this order toward the tip side. The diameter of each of the protrusions (41D, 42D, 43D) around the central axis C1 gradually decreases in the order of the protrusions (41D, 42D, 43D).

[0079] Each of the protrusions (41D to 43D) has a planar shape with a leading edge slope (431) and a leading edge slope (432) extending outward from the outer surface of the leading edge connecting part (3A). Hereinafter, the protrusion (42D) will be described as an example.

[0080] In the protrusion (42D), the portion connecting to the tip connecting portion (3A) that is adjacent to the tip portion (3D) of the tip connecting portion (3A) is called the tip portion (435). The tip slope portion (431) extends from the tip portion (435) at an angle toward the base side with respect to the diameter direction. In the protrusion (42D), the portion connecting to the tip connecting portion (3A) that is adjacent to the tip portion (30D) of the expansion portion (3B) is called the base portion (436). The base slope portion (432) extends from the base portion (436) at an angle toward the tip side with respect to the diameter direction. The end of the tip slope portion (431) opposite to the tip portion (435) and the end of the base slope portion (432) opposite to the base portion (436) are connected at the apex (430). The angle θ32 of the base slope portion (432) relative to the tip connection portion (3A) is greater than the angle θ31 of the tip slope portion (431) relative to the tip connection portion (3A).

[0081] <Operation and Effect of Third Embodiment>

[0082] The balloon catheter (1C) can allow the protrusion (4D) to penetrate into the stenotic lesion (90A) over a wide range of the peripheral direction at the tip connection (3A). Thus, the balloon catheter (1C) can prevent the balloon (3) from moving in the opposite direction to the direction of entry into the stenotic lesion (90A) by means of the protrusion (4D) when the balloon (3) is inflated.

[0083] <Special Notes on the Third Embodiment>

[0084] The number and shape of the protrusions in the protrusion (4D) are not limited to the above embodiment. For example, the vertex (430) of each of the protrusions (41D to 43D) may be curved in a convex shape toward the outside. An annular protrusion extending in a peripheral direction around the central axis C1 may also be provided in the tip extension installation part (220) of the inner tube (22). A connecting part connecting the protrusions (41D to 43D) may be extended in an elongation direction along the outer surface of the tip connecting part (3A).

[0085] <4th embodiment (balloon catheter (1D))>

[0086] Referring to FIG. 8, a balloon catheter (1D) will be described. The balloon catheter (1D) differs from the balloon catheter (1C) in that it has a protrusion (4E) instead of a protrusion (4D). Hereinafter, the description of the balloon catheter (1D) that is identical to the balloon catheter (1C) will be omitted.

[0087] The protrusion (4E) is provided on the outer surface of the leading edge connecting part (3A) of the balloon (3) and protrudes outward. The protrusion (4E) has a spiral shape that extends in a peripheral direction around the central axis C1. The leading edge end (447) of the protrusion (4E) is located near the leading edge with respect to the leading edge (30D) of the expansion part (3B) of the balloon (3). The leading edge end (448) of the protrusion (4E) is located near the leading edge with respect to the leading edge (3D) of the leading edge connecting part (3A).

[0088] The portion of the protrusion (4E) that is connected to the tip connecting portion (3A) and is adjacent to the tip portion (3D) of the tip connecting portion (3A) is called the tip portion (445). The planar portion extending from the tip portion (445) at an angle toward the base side with respect to the diameter direction is called the tip slope portion (441). The portion of the protrusion (4E) that is connected to the tip connecting portion (3A) and is adjacent to the tip portion (30D) of the expansion portion (3B) is called the base portion (446). The planar portion extending from the base portion (446) at an angle toward the tip side with respect to the diameter direction is called the base slope portion (442). The end of the tip slope portion (441) opposite to the tip portion (445) and the end of the base slope portion (442) opposite to the base portion (446) are connected at the apex (440). The angle θ42 of the base slope portion (442) relative to the tip connection portion (3A) is greater than the angle θ41 of the tip slope portion (441) relative to the tip connection portion (3A).

[0089] <Operation and Effect of the 4th Embodiment>

[0090] The balloon catheter (1D) can apply the protrusion (4E) to the stenotic lesion (90A) over a wide range of the peripheral and elongation directions at the tip connection (3A). Accordingly, the balloon catheter (1D) can prevent the balloon (3) from moving in the opposite direction to the entry direction toward the stenotic lesion (90A) by means of the protrusion (4E) when the balloon (3) is inflated.

[0091] <Special Notes on the 4th Embodiment>

[0092] The shape of the protrusion (4E) is not limited to the above embodiment. For example, the apex (440) of the protrusion (4E) may be curved in a convex shape toward the outside. A spiral-shaped protrusion extending in a peripheral direction around the central axis C1 may also be provided on the tip extension installation part (220) of the inner tube (22).

[0093] <Fifth embodiment (balloon catheter (1E))>

[0094] Referring to FIG. 9, a balloon catheter (1E) will be described. The balloon catheter (1E) is different from the balloon catheter (1A) in that the protrusion (4B) is not provided on the tip extension installation part (220). In addition, the shape of the tip connection part (3A) of the balloon (3) is different from that of the balloon catheter (1A). Hereinafter, the description of the balloon catheter (1E) that is identical to the balloon catheter (1A) will be omitted.

[0095] The leading edge connecting part (3A) of the balloon (3) has inclined parts (36, 37, 38). In the balloon (3) in an inflated state, the inclined part (36) extends outward from the leading edge (3D) of the leading edge connecting part (3A) toward the base side while expanding. The inclined part (37) extends outward from the end opposite to the end connected to the leading edge (3D) in the direction of elongation of the inclined part (36) while expanding toward the base side. The inclined part (38) extends outward from the end opposite to the end connected to the inclined part (36) in the direction of elongation of the inclined part (37) while expanding toward the base side.

[0096] For the inclined sections (36 to 38), the angle formed between the direction extending from the end near the leading edge (3D) toward the end near the leading edge (30D) and the direction of elongation is defined as the inclination angle. The inclination angle in the inclined section (36) is denoted as θ51, the inclination angle in the inclined section (37) is denoted as θ52, and the inclination angle in the inclined section (38) is denoted as θ53. In this case, the inclination angles θ51, θ52, and θ53 are different from each other. The inclination angles θ51 to θ53 have a relationship of magnitude such that θ52 < θ51 < θ53. The inclination angle θ53 is the largest, and the inclination angle θ52 is the smallest.

[0097] The shape of the protrusions (41A, 42A) of the protrusion (4A) is the same as that of the balloon catheter (1A). The protrusions (41A, 42A) are provided on the inclined section (37) which has the smallest inclination angle θ52 among the inclined sections (36 to 38).

[0098] A virtual plane S0 is defined connecting the leading edge (30D) of the expansion portion (3B) of the balloon (3) and the leading edge (3D) of the balloon (3). In this case, the protrusions (41A, 41B) are located on the side closer to the central axis C1 with respect to the virtual plane S0, that is, on the inner side with respect to the virtual plane S0.

[0099] <Operation and Effect of the Fifth Embodiment>

[0100] When the balloon (3) is inflated, the inclined portions (36 to 38) of the tip connecting portion (3A) move in a direction perpendicular to each of them. Here, the direction of movement of the inclined portion (37) with a relatively small inclination angle θ52 is closer to the diameter direction than the direction of movement of the inclined portions (36, 38) with relatively large inclination angles θ51 and θ53. Additionally, as the direction of movement of the protrusion (4A) during the inflation of the balloon (3) approaches the diameter direction, the protrusion (4A) becomes more likely to penetrate into the stenotic lesion (90A) of the blood vessel (9).

[0101] In the balloon catheter (1E), a protrusion (4A) is provided on an inclined portion (37) with a relatively small inclination angle θ52. When the balloon (3) is inflated, the protrusion (4A) moves in a direction perpendicular to the inclined portion (37). Additionally, since the inclination angle θ52 is defined as an angle of the inclined portion (37) relative to the elongation direction, when the inclination angle θ52 is small, the angle between the direction perpendicular to the inclined portion (37), that is, the direction of movement of the protrusion (4A) during the inflation of the balloon (3), and the diameter direction perpendicular to the elongation direction also becomes smaller. In other words, when the balloon (3) is inflated, the protrusion (4A) moves in a direction approximately equal to the diameter direction. Because of this, the balloon catheter (1E) can cause the protrusion (4A) to properly penetrate into the stenotic lesion (90A) when the balloon (3) is inflated.

[0102] <Special details of the 5th embodiment>

[0103] The shape of the protrusion (4A) provided on the inclined portion (37) is not limited to the above embodiment. For example, the protrusion may have the shape of the protrusion (4D) in the third embodiment (annular shape) or the shape of the protrusion (4E) in the fourth embodiment (spiral shape). The inclination angles θ51 and 53 may be the same. The number of inclined portions of the tip connecting portion (3A) is not limited to three, but may be two or four or more. If there are three or more inclined portions, protrusions may be provided on multiple inclined portions where the inclination angle is smaller than a predetermined threshold. The protrusion (4A) may protrude outward with respect to the virtual plane S0.

[0104] <6th embodiment (balloon catheter (1F))>

[0105] Referring to FIG. 10, a balloon catheter (1F) will be described. The balloon catheter (1F) differs from the balloon catheter (1A) in that it has protrusions (4G, 4H) in addition to the protrusion (4A), and does not have a protrusion (4B). Hereinafter, the description of the balloon catheter (1F) that is identical to the balloon catheter (1A) will be omitted.

[0106] The protrusion (4G) is provided on the outer surface of the expansion portion (3B) of the balloon (3) and protrudes outward. The protrusion (4G) has protrusions (41G, 42G). Each of the protrusions (41G, 42G) extends in an elongation direction across the front end (30D) and the base end (30P) of the expansion portion (3B). The protrusions (41G, 42G) face each other with respect to the central axis C1. The circumferential positions of the protrusions (41A, 41G) coincide. The circumferential positions of the protrusions (42A, 42G) coincide.

[0107] The shape of the protrusions (41G, 42G) is identical. Below, the shape is described using the protrusion (41G) as an example. The protrusion (41G) has a base portion (51) and a tip portion (52). The shape of the base portion (51) is a square column and extends in the elongation direction. The side (51A) of the base portion (51) connects to the outer surface of the expansion portion (3B) of the balloon (3). The shape of the tip portion (52) is a triangular column and extends in the elongation direction. The side (52A) of the tip portion (52) connects to the side (51B) of the base portion (51) that is opposite to the side (51A). The sides (52B, 52C) of the tip portion (52), other than the side (52A), are connected at the apex (520). The distance between the sides (51A, 52B) of the base (51) and the distance between the side (52A) of the tip (52) and the apex (520) are equal.

[0108] In the cross-section of the protrusion (41G), two end portions (510) are defined in the direction perpendicular to the elongation direction of the side portion (51A). Additionally, two virtual line segments S1 are defined connecting each of the two end portions (510) and the vertex (520). In this case, parts of the base portion (51) and the tip portion (52) of the protrusion (41G) are positioned outside the virtual triangle (hereinafter referred to as "virtual triangle T1") defined by the two virtual line segments S1 and the side portion (51A).

[0109] The protrusion (4H) is provided on the inner surface of the leading portion (3A) of the balloon (3) and protrudes inward. The protrusion (4H) has protrusions (41H, 42H). The protrusion (41H) extends between the leading portion end of the protrusion (41G) and the protrusion (41A). The protrusion (42H) extends between the leading portion end of the protrusion (42G) and the protrusion (42A). The protrusion (4H) is interposed between the protrusions (4A, 4G) and connects the protrusions (4A, 4G) on the inside of the balloon (3).

[0110] <Operation and Effect of the 6th Embodiment>

[0111] In the balloon catheter (1F), the rigidity of the part of the balloon (3) where the protrusion (4H) is provided and the rigidity of the part of the balloon (3) where the protrusion (4A) is provided can be made equal. Because of this, when the balloon (3) is inflated, the protrusion (4A) can be prevented from being pushed back toward the central axis C1 by the protrusion (4H) due to stress from the stenotic lesion (90A). The protrusion (4H) protrudes inward from the inner surface of the tip connecting part (3A) of the balloon (3) and does not protrude outward from the outer surface. Because of this, the balloon catheter (1F) can prevent a decrease in the passability of the balloon (3) caused by the provision of the protrusion (4H).

[0112] When the balloon (3) contracts, a force directed inward is applied to the portion of the balloon (3) where the protrusion (4H) is provided. In this case, it becomes easier for a blade to form during the process of the balloon (3) contracting. Additionally, by folding the blade formed in the contracted state, the diameter of the balloon (3) in the contracted state is minimized. Therefore, the balloon catheter (1F) can properly form a blade by the protrusion (4H) in the contracted state of the balloon (3), thereby making the diameter of the balloon (3) in the contracted state smaller.

[0113] In the cross-section of the protrusions (41G, 42G) of the protrusion (4G), each part of the base portion (51) and the tip portion (52) is positioned outward with respect to the virtual triangle T1. Because of this, the protrusions (41G, 42G) are difficult to collapse even when an external force is applied. Therefore, the balloon catheter (1F) can apply the protrusion (4G) as well as the protrusion (4A) to the stenotic lesion (90A) when the balloon (3) is inflated, so the stenotic lesion (90A) can be properly treated.

[0114] <Special Notes on the 6th Embodiment>

[0115] In the portion of the leading edge connecting part (3A) of the balloon (3) where the protrusion (4H) is provided on the inner surface, a third convex portion protruding outwardly may be provided on the outer surface. Additionally, the amount of protrusion of the third convex portion is smaller than the amount of protrusion of the protrusion (4A). The ratio of the amount of protrusion of the third convex portion to the amount of protrusion of the protrusion (4A) is not particularly limited, but as an example, it is 50% or less, more preferably 10% or less.

[0116] As shown in FIG. 11, the protrusion (4H) may also extend between the end of the protrusion (4G) and the front end (3D) of the balloon (3). In this case, the protrusion (4H) may be provided on the inner surface of the front end connecting part (3A) of the balloon (3) between the end of the protrusion (4G) and the front end (3D) of the balloon (3).

[0117] The protrusion (4G) may be provided on the inner surface of the expansion portion (3B) of the balloon (3) and may protrude inward. The protrusion (4G) may be formed in a ring shape along the circumferential direction centered on the central axis C1. In this case, the protrusion (4G) may be formed only near the tip portion (30D) of the expansion portion (3B) of the balloon (3).

[0118] The protrusion (4H) may be provided on the entire surface of the inner surface of the leading edge connecting part (3A) of the balloon (3), in the elongation direction, on the lower side of the protrusion (4A).

[0119] The hardness of each of the protrusions (41G, 42G) of the protrusion (4G) may be uniform throughout or may vary from part to part. For example, as shown in FIG. 12a, the hardness of each of the protrusions (41G, 42G) may gradually become harder from the side (51A) toward the apex (520). In this case, the protrusions (41G, 42G), especially the area near the apex (520), can be made difficult to collapse even when an external force is applied, so that when the balloon (3) is inflated, the protrusions (4G) can be properly penetrated into the constricted lesion (90A). In addition, flexibility can be maintained in the area near the part of the protrusions (41G, 42G) that connects with the balloon (3). Because of this, when the balloon (3) passes through the blood vessel (9), the reduction in passage due to the protrusions (4G) getting caught on the inner wall can be mitigated.

[0120] For example, as shown in FIG. 12b, for the protrusions (41G, 42G), a virtual center S2 is defined as a virtual line segment extending in the radial direction through the vertex (520). For each base portion (51) of the protrusions (41G, 42G), a side portion (51C, 51D) is defined excluding the side portion (51A, 51B). In this case, the hardness of each of the protrusions (41G, 42G) may gradually become harder from each of the side portions (51C, 51D, 52B, 51C) toward the virtual center S2. Additionally, for example, as shown in FIG. 12c, in the cross-section of the protrusions (41G, 42G), the hardness of the portion positioned inward with respect to the virtual triangle T1 may be higher than the hardness of the portion positioned outward with respect to the virtual triangle T1.

[0121] In the case of the example shown in FIG. 12b and FIG. 12c, the protrusion (4G) is stably positioned on the outer surface of the balloon (3) so that it is difficult to collapse even when an external force is applied. Because of this, when the balloon (3) is inflated, the protrusion (4G) can be properly dug into the constricted lesion (90A).

[0122] The shape of the protrusion (4G) is not limited to the above embodiment. Variations regarding the shape of the protrusions (41G, 42G) of the protrusion (4G) (see FIG. 13a), (47G) (see FIG. 13b), (48G) (see FIG. 13c)) will be described. Hereinafter, the direction extending in the diameter direction from the central axis C1 of the balloon (3) through the vertex (520) is called the "protrusion direction." The direction that is orthogonal to the elongation direction and also orthogonal to the protrusion direction is called the "orthogonal direction."

[0123] The protrusion (46G) shown in FIG. 13a has a base portion (51) and has base elements (511, 512). Each of the base elements (511, 512) has a shape that is a square column and extends in the elongation direction. The side (512A) of the base element (512) is connected to the expansion portion (3B) of the balloon (3). The side (511A) of the base element (511) is connected to the side (512B) of the base element (512) that is opposite to the side (512A). The side (52A) of the tip portion (52) is connected to the side (511B) of the base element (511) that is opposite to the side (511A).

[0124] The length of the orthogonal direction of the base element (511) is shorter than the length of the orthogonal direction of the base element (512). The length of the side (52A) of the tip portion (52) is shorter than the length of the orthogonal direction of the base element (511). In the cross-section of the protrusion (46G), a portion including both ends of the orthogonal direction of the base elements (511, 512) and the tip portion (52) is positioned outside of the virtual triangle T1. The length of the protrusion direction of the base portion (51) is longer than the length of the protrusion direction of the tip portion (52).

[0125] The protrusion (46G) can stably support the tip (52) by the base (51). Because of this, when the balloon (3) expands, the tip (52) of the protrusion (46G) can properly penetrate into the constricted lesion (90A).

[0126] The protrusion (47G) shown in FIG. 13b has a shape of the base element (512) that is different from the protrusion (46G) (see FIG. 13a). The shape of the base element (512) is a prism with a trapezoidal cross-section. The side (512B) of the base element (512) is shorter than the side (512A). Also, the side (512B) is longer than the side (511A) of the base element (511).

[0127] Among the base elements (512), the sides (512C, 512D) are defined, excluding the sides (512A, 512B). The direction extending from the side (512A) side to the side (512B) side along the sides (512C, 512D) is inclined in a direction approaching the virtual center S2 passing through the vertex (520). In the cross-section of the protrusion (47G), a portion including both ends of the respective orthogonal directions of the base elements (511, 512) and the tip (52) is positioned outside the virtual triangle T1.

[0128] The protrusion (48G) shown in FIG. 13c has a shape of the base element (511) that is different from the protrusion (47G) (see FIG. 13b). The shape of the base element (511) is a prism with a trapezoidal cross-section. The side (511B) of the base element (511) is shorter than the side (511A). Also, the side (511B) is longer than the side (52A) of the tip portion (52).

[0129] Among the base elements (511), the sides (511C, 511D) are defined, excluding the sides (511A, 511B). The direction extending from the side (511A) side to the side (511B) side along the sides (511C, 511D) is inclined in a direction approaching the virtual center S2 passing through the vertex (520). In the cross-section of the protrusion (48G), a portion including both ends of the respective orthogonal directions of the base elements (511, 512) and the tip (52) is positioned outside the virtual triangle T1.

[0130] In the protrusions (47G, 48G), the tip portion (52) can be supported more stably by the base portion (51). Because of this, the protrusions (47G, 48G) can properly act on each tip portion (52) in the constricted lesion (90A) when the balloon (3) is inflated. In addition, since the step difference in the orthogonal direction of the protrusions (47G, 48G) can be reduced, it becomes difficult for the protrusions (47G, 48G) to collapse even if the protrusion amount is increased. Because of this, by increasing the protrusion amount of the protrusions (47G, 48G), the protrusions (47G, 48G) can be properly penetrated into the constricted lesion (90A) when the balloon (3) is inflated.

[0131] <7th Embodiment (Balloon Catheter (1G))>

[0132] Referring to FIG. 14, a balloon catheter (1G) will be described. The balloon catheter (1G) is different from the balloon catheter (1A) in that it does not have a protrusion (4A) and has a protrusion (4I) instead of a protrusion (4B). Hereinafter, the description of the balloon catheter (1G) that is identical to the balloon catheter (1A) will be omitted.

[0133] The protrusion (4I) has protrusions (41I, 42I, 43I, 44I, 45I, 46I). The protrusions (41I to 46I) are provided on the outer surface of the tip extension installation part (220) of the inner tube (22) and protrude outward. The protrusions (41I, 42I, 43I) are arranged along the elongation direction. The circumferential positions of the protrusions (41I, 42I, 43I) coincide. The protrusions (44I, 45I, 46I) are arranged along the elongation direction. The circumferential positions of the protrusions (44I, 45I, 46I) coincide. The protrusions (41I, 44I) are close to the tip (30D) of the balloon (3). The protrusions (43I, 46I) are close to the tip portion (221) of the inner tube (22). The protrusions (41I, 44I) are opposite each other with respect to the central axis C1. The protrusions (42I, 45I) are opposite each other with respect to the central axis C1. The protrusions (41I, 44I) are opposite each other with respect to the central axis C1.

[0134] The shape of the protrusions (41I to 46I) and the shape of the protrusions (41B, 42B) of the protrusion (4B) in the balloon catheter (1A) (see FIG. 1) are analogous. The respective tip (465), base (466), tip slope (461), base slope (462), apex (460), and angles θ61, θ62 of the protrusions (41I to 46I) correspond to the respective tip (425), base (426), tip slope (421), base slope (422), apex (420), and angles θ21, θ22 of the protrusions (41B, 42B) of the protrusion (4B). The angle θ62 of the base slope portion (462) relative to the tip extension installation portion (220) is greater than the angle θ61 of the tip slope portion (461) relative to the tip extension installation portion (220).

[0135] The protrusions (41I, 42I, 43I) differ from each other in the distance from the tip extension installation part (220) to the apex (460), i.e., the amount of protrusion. Among the protrusions (41I, 42I, 43I), the protrusion (43I) closest to the tip (221) of the inner tube (22) has the smallest amount of protrusion, and the protrusion (41I) closest to the tip (3D) of the balloon (3) has the largest amount of protrusion. The amount of protrusion of each protrusion (41I, 42I, 43I) increases as it approaches the tip (3D) of the balloon (3).

[0136] The protrusions (44I, 45I, 46I) each have different protrusion amounts. Among the protrusions (44I, 45I, 46I), the protrusion (46I) closest to the tip (221) of the inner tube (22) has the smallest protrusion amount, and the protrusion (44I) closest to the tip (3D) of the balloon (3) has the largest protrusion amount. The protrusion amount of each protrusion (44I, 45I, 46I) increases as it approaches the tip (3D) of the balloon (3).

[0137] <Operation and Effect of the 7th Embodiment>

[0138] In the balloon catheter (1G), the protrusion (4I) can suppress the resistance received from the stenotic lesion (90A) during the process in which the tip extension installation part (220) of the inner tube (22) advances through the lumen of the stenotic lesion (90A). Because of this, the balloon catheter (1G) can reduce the retraction of the balloon (3) by the resistance received by the protrusion (4I) from the stenotic lesion (90A).

[0139] The balloon catheter (1G) has protrusions (41I to 43I, 44I to 46I) arranged in the elongation direction. Because of this, compared to the case of a balloon catheter (1A) having only protrusions (41A, 41B), it becomes difficult to be pushed back when resistance is received from the stenotic lesion (90A) during the process in which the tip extension installation part (220) of the inner tube (22) advances through the lumen of the stenotic lesion (90A). Therefore, the balloon catheter (1G) can more efficiently perform the operation of advancing the balloon (3) little by little towards the distal side while repeatedly changing the balloon (3) between an inflated state and a contracted state.

[0140] <Special Notes on the 7th Embodiment>

[0141] The protrusion amounts of the protrusions (41I to 46I) may be the same. Alternatively, the protrusion amounts of the protrusions (42I, 43I, 45I, 46I) may be the same, and the protrusion amount of the protrusions (41I, 44I) may be smaller than the protrusion amount of the protrusions (42I, 43I, 45I, 46I). The peripheral positions of each of the protrusions (41I to 43I) may be different. Likewise, the peripheral positions of each of the protrusions (44I to 46I) may be different. The balloon catheter (1G) may have a protrusion (4A) on the tip connection portion (3A) of the balloon (3).

[0142] <8th Embodiment>

[0143] Referring to FIG. 15, a balloon catheter (1H) will be described. The balloon catheter (1H) differs from the balloon catheter (1A) (see FIG. 1) in that the balloon (3) has a tip joint (3J), has only a protrusion (4A) and does not have a protrusion (4B), and has additionally a tip chip (6A) and a cover tube (7A). Hereinafter, the description of the balloon catheter (1H) that is identical to the balloon catheter (1A) will be omitted.

[0144] The balloon (3) of the balloon catheter (1H) has a tip joint (3J) that extends toward the tip side from the tip portion (3D) of the tip connection portion (3A). The tip joint (3J) is extended along the outer surface of the inner tube (22) and is joined to the inner tube (22). Hereinafter, the tip side end of the tip joint (3J) is referred to as the "tip portion (300D)".

[0145] A tip chip (6A) is provided at the tip portion (221) of the inner tube (22). The tip chip (6A) is made of a flexible resin. The tip chip (6A) prevents scratches from forming on the blood vessel (9) when the tip portion (221) of the inner tube (22) collides with the inner wall of the blood vessel (9).

[0146] The tip chip (6A) has a belly (61) and an elongation portion (62). The belly (61) covers the tip portion (221) of the inner tube (22) from the tip side. The belly (61) is provided with a through hole (61A) for passing a guide wire inserted through the inner tube (22). The diameter of the through hole (61A) is smaller than the diameter of the inner lumen of the inner tube (22). The elongation portion (62) extends from the outer end of the belly (61) to the base side along the outer surface of the inner tube (22). The base end of the elongation portion (62) (hereinafter referred to as the "base portion (62P)") is spaced apart from the tip portion (300D) of the tip joint (3J) of the balloon (3) to the tip side. Among the inner tube (22), the portion that is closer to the base portion (62P) and closer to the tip portion (300D) in the elongation direction is not covered by the tip chip (6A) and the tip joint portion (3J). Hereinafter, the portion of the inner tube (22) that is not covered by the tip chip (6A) and the tip joint portion (3J) is referred to as the "exposed portion (226)."

[0147] The cover tube (7A) has a tubular shape. The cover tube (7A) covers the portion near the base portion (62P) of the extended portion (62) of the tip chip (6A), the portion near the tip portion (300D) of the tip joint portion (3J) of the balloon (3), and the exposed portion (226) of the inner tube (22) from the outside. The hardness of the cover tube (7A) is uniform.

[0148] The cover tube (7A), tip chip (6A), and balloon (3) are melted by heat. Heat is applied to the vicinity of the tip of the balloon catheter (1H) in the state shown in FIG. 15. As a result, the portion near the base (62P) of the extended portion (62) of the cover tube (7A) and tip chip (6A), and the portion near the tip (300D) of the tip joint (3J) of the balloon (3) are melted and welded together. Because of this, the step difference appearing in FIG. 15, the portion near the base (62P) of the extended portion (62) of the cover tube (7A) and tip chip (6A), and the portion near the tip (300D) of the tip joint (3J) of the balloon (3) is resolved as the cover tube (7A), melted by heating, enters the stepped portion. The same applies to FIGS. 16a, 16b, and 16c described later.

[0149] <Operation and Effect of the 8th Embodiment>

[0150] In the case where the cover tube (7A) is not provided, the hardness of the portion of the balloon (3) that is closer to the tip (3D) of the balloon catheter (1H) differs in each of the following regions in the elongation direction: region W6, which is closer to the tip than the base (62P); region W7, which is between the base (62P) and the tip (300D); and region W8, which is closer to the tip than the tip (300D). The hardness of region W7 is more flexible than the hardness of regions W6 and W8. This is because, while the inner tube (22) and the tip chip (6A) are arranged in region W6 and the inner tube (22) and the tip joint (3J) are arranged in region W8, only the inner tube (22) is arranged in region W7. Here, in order to ensure good tracking of the guide wire, it is preferable that the difference in hardness between regions W6 and W8 be small.

[0151] In contrast, in the balloon catheter (1H), a cover tube (7A) is provided at a position overlapping with region W7. The hardness of region W7 becomes harder than the hardness of region W6, and the hardness of region W8 becomes harder than the hardness of region W7 (hardness of region W6 < hardness of region W7 < hardness of region W8). By making the hardness of region W7 harder through the cover tube (7A), the difference in hardness between regions W6, W8 and region W7 can be reduced. Therefore, the balloon catheter (1H) can improve the tracking ability of the guide wire at the tip portion.

[0152] <Special Notes on the 8th Embodiment>

[0153] Variations of the cover tube, such as cover tubes (7B) (Fig. 16a), (7C) (Fig. 16b), and (7D) (Fig. 16c), will be described.

[0154] The difference between the cover tube (7B) shown in FIG. 16a and the cover tube (7A) is that the diameter of a portion of the outer surface is expanded toward the base side, and the end of the cover tube (7B) on the front side is located inward relative to the elongated portion (62) of the front chip (6A). In addition, the end of the cover tube (7B) on the front side is located outside the front joint (3J) of the balloon (3), just like the cover tube (7A), and covers the area near the front portion (300D) of the front joint (3J) from the outside.

[0155] The difference between the cover tube (7C) shown in FIG. 16b and the cover tube (7A) is that the end of the front end of the cover tube (7C) is located inward with respect to the elongation portion (62) of the front chip (6A), and the end of the base end of the cover tube (7C) is located inward with respect to the front joint portion (3J). In this case, the cover tube (7C) extends in the elongation direction along the outer surface of the inner tube (22) over the entire length.

[0156] The difference between the cover tube (7D) shown in FIG. 16c and the cover tube (7A) is that the hardness is not uniform. The hardness of the cover tube (7D) is harder in the portion corresponding to region W7 than in the portion corresponding to regions W6 and W8. By doing so, the difference in hardness between regions W6 and W8 in the balloon catheter (1H) can be made smaller, thereby improving the tracking ability of the guide wire at the tip portion. Additionally, the cover tube (7D) may be formed from different materials for each of the regions W6 to W8 with different hardness. Furthermore, the hardness may be controlled by making the physical properties different for each of the portions corresponding to regions W6 to W8 within the cover tube (7D) containing a common material.

[0157] Additives to improve sliding mobility may be added to the cover tubes (7A to 7D).

[0158] Others

[0159] The base portion (212, 222) is an example of the “first base portion” of the present invention. The tip portion (221) is an example of the “first tip portion” of the present invention. The tip portion (30D) is an example of the “second tip portion” of the present invention. The tip portion (3D) is an example of the “third tip portion” of the present invention. The protrusions (4A, 4C to 4E) are examples of the “first protrusions” of the present invention. The protrusions (4B, 4I) are examples of the “second protrusions” of the present invention. The apex (410) is an example of the “first apex” of the present invention. The tip gradient portion (411) is an example of the “first tip gradient portion” of the present invention. The base gradient portion (412) is an example of the “first base gradient portion” of the present invention. The protrusion (4G) is an example of the "third protrusion" of the present invention. The protrusion (4H) is an example of the "inner protrusion" of the present invention. The apex (420) is an example of the "second apex" of the present invention. The leading edge gradient (421) is an example of the "second leading edge gradient" of the present invention. The base gradient (422) is an example of the "second base gradient" of the present invention.

Claims

Claim 1 A catheter shaft extending in an elongation direction across a first base portion and a first tip portion; a balloon connected to a position in the catheter shaft where the distance to the first tip portion is shorter than the distance to the first base portion; an expansion portion having a tubular shape extending in the elongation direction; a portion extending opposite to the expansion portion from a second tip portion, which is the end portion closest to the first tip portion among the two ends of the expansion portion in the elongation direction, wherein the diameter of the end portion connected to the expansion portion is larger than the diameter of the third tip portion, which is the end portion opposite to the end portion connected to the expansion portion, and the balloon having a tip connection portion connected to the catheter shaft at the third tip portion; and a protrusion protruding outward in a diameter direction with respect to the central axis of the catheter shaft, and comprising at least a first protrusion provided in a portion including the tip connection portion and the third tip portion of the balloon, wherein the tip connection portion is closest to the second tip portion among the protrusions A balloon catheter characterized by having at least a region between the end portion and the second tip portion having a protrusion amount smaller than the protrusion amount of the protrusion portion. Claim 2 A balloon catheter according to claim 1, wherein the first protrusion comprises a first vertex most protruding outwardly in the diameter direction, a first tip gradient extending toward the first vertex from an end on the side adjacent to the third tip, and a first base gradient extending toward the first vertex from an end on the side adjacent to the second tip, wherein the angle of the first base gradient with respect to the tip connection portion is greater than the angle of the first tip gradient with respect to the tip connection portion. Claim 3 A balloon catheter according to claim 1 or 2, wherein the protrusion further comprises a third protrusion provided in the expansion portion of the balloon, and has an inner protrusion that extends between the first protrusion and the third protrusion and protrudes inward in the diameter direction from the inner surface of the tip connecting portion. Claim 4 A balloon catheter according to claim 1 or 2, wherein the first protrusion has a ring shape extending in a peripheral direction around the central axis. Claim 5 A balloon catheter according to claim 1 or 2, wherein the first protrusion has a spiral shape extending in a peripheral direction around the central axis. Claim 6 A balloon catheter according to claim 1 or 2, wherein the tip connecting portion has a plurality of inclined portions, and the plurality of inclined portions each include at least two inclined portions in which the angle of inclination between the direction extending from the second tip portion side toward the third tip portion side and the central axis is different from each other, and the first protrusion is provided in the inclined portion having the smallest angle of inclination among the plurality of inclined portions. Claim 7 A balloon catheter according to claim 1 or 2, wherein the protrusion comprises a second protrusion provided in a tip extension installation portion which is a portion between the third tip portion and the first tip portion of the balloon in the elongation direction. Claim 8 A balloon catheter according to claim 7, wherein the second protrusion has a plurality of protrusions, and the protrusion amount of each of the plurality of protrusions is larger as it approaches the third tip. Claim 9 A balloon catheter according to claim 7, wherein the second protrusion comprises a second vertex most protruding outwardly in the diameter direction, a second tip gradient extending toward the second vertex from an end on the side adjacent to the first tip, and a second base gradient extending toward the second vertex from an end on the side adjacent to the third tip, wherein the angle of the second base gradient relative to the tip extension installation part is greater than the angle of the second tip gradient relative to the tip extension installation part. Claim 10 A balloon catheter according to claim 7, wherein the tip extension installation portion has at least an area between the end closest to the first tip portion among the protrusions and the first tip portion, the area having a protrusion amount smaller than the protrusion amount of the protrusion. Claim 11 delete Claim 12 delete

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