Balloon catheter

Abstract

A balloon catheter (1A) has a catheter shaft (2), a balloon (3), and protrusions (4A, 4B). The balloon (3) has an inflation portion (3B) and a front end connecting portion (3A) that is a portion extending from a front end portion (30D) of both end portions of the inflation portion (3B) to the side opposite to the inflation portion (3B) and that is connected to the catheter shaft (2) at the front end portion (3D) having a larger diameter than the diameter of the front end portion (3D) as the end portion on the opposite side. The protrusions (4A, 4B) protrude to the outer side in the radial direction with respect to the central axis (C1) of the catheter shaft (2). The protrusion (4A) is provided to the front end connecting portion (3A). The protrusion (4B) is provided to a front end extension portion (220) of the inner tube (22). The front end connecting portion (3A) has at least a region between the protrusion (4A) and the front end portion (30D) having a smaller protrusion amount than the protrusion amount of the protrusion (4A).

Description

Technical Field

[0001] This invention relates to balloon catheters. Background Technology

[0002] Patent document 1 discloses a balloon catheter with a linear protrusion in the balloon. The linear protrusion is provided in the entire area along the axial direction of the balloon, within the conical region at the base, the straight tube region, and the conical region at the front end. The linear protrusion protrudes outward from the outer surface of the balloon.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: International Publication No. 2020 / 012850 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] When a balloon is inserted into a blood vessel, the following problems exist: sometimes the linear protrusion in the cone-shaped area at the front end gets caught on the inner wall of the blood vessel, which reduces the permeability of the balloon.

[0008] The object of the present invention is to provide a balloon catheter that enables good balloon passage even when the protrusion is located at the anterior end of the balloon.

[0009] Solution for solving the problem

[0010] The balloon catheter of the present invention is characterized by comprising: a catheter shaft extending in an extending direction over a entire range between a first base end and a first anterior end; a balloon connected to the catheter shaft at a position where the distance between the balloon and the first anterior end is shorter than the distance between the balloon and the first base end, and having an expansion portion and a front end connecting portion, the expansion portion having a cylindrical shape extending in the extending direction, the front end connecting portion being a portion extending from a second anterior end, which is the end closest to the first anterior end, towards a side opposite to the expansion portion, and the diameter of the end of the front end connecting portion connected to the expansion portion being equal to the diameter of the end connected to the expansion portion. The third front end portion of the opposite end has a large diameter, and the front end connection portion is connected to the catheter shaft at the third front end portion; and a protrusion that protrudes radially outward relative to the central axis of the catheter shaft, and includes at least one of a first protrusion disposed on the front end connection portion of the balloon and a second protrusion disposed on the front end extension portion, the front end extension portion being a portion disposed in the extension direction between the third front end portion and the first front end portion of the balloon, and the front end connection portion having at least a region between the end of the protrusion closest to the second front end portion and the second front end portion having a protrusion amount smaller than the protrusion amount of the protrusion.

[0011] The balloon catheter allows for a smaller area at the tip connector compared to a protrusion covering the entire tip connector. Therefore, even with a protrusion, the balloon catheter provides good passage through the blood vessel.

[0012] In this invention, the protrusion may also include the first protrusion. In this case, the balloon catheter allows the first protrusion to act on the lesion during repeated balloon inflation / contraction to dilate the lesion within the blood vessel. In this case, the balloon catheter allows the balloon to advance gradually relative to the lesion with a small lumen, thus effectively dilating the lesion.

[0013] In this invention, the first protrusion may also include: a first apex, which protrudes most outward in the radial direction; a first frontal ramp, which extends from an end near the third frontal portion toward the first apex; and a first base ramp, which extends from an end near the second frontal portion toward the first apex, wherein the angle of the first base ramp relative to the frontal connection is larger than the angle of the first frontal ramp relative to the frontal connection. In this case, the balloon catheter can suppress resistance from the lesion during balloon advancement. Therefore, the balloon catheter can reduce the situation where the balloon is pushed back due to resistance from the lesion during balloon advancement.

[0014] In this invention, the first protrusion may also be disposed on the portion including the third anterior end. In this case, when the balloon catheter can enter the lesion within the blood vessel through the third anterior end and repeatedly inflate / contract the balloon to expand the lesion, the first protrusion at the third anterior end can be used to prevent the balloon from being pushed back in the opposite direction of travel.

[0015] In this invention, the protrusion may also include a third protrusion disposed on the expansion portion of the balloon, and the balloon catheter has an inner protrusion extending over the entire range between the first and third protrusions, and protruding radially inward from the inner surface of the front end connector. In this case, the balloon catheter allows the rigidity of the portion of the balloon with the inner protrusion to be equal to the rigidity of the portion of the balloon with the first protrusion. Therefore, the inner protrusion can be used to suppress the first protrusion from being pushed back towards the central axis due to stress from the lesion during balloon inflation. It should be noted that the inner protrusion protrudes inward from the inner surface of the front end connector, thus suppressing the reduction of balloon permeability.

[0016] In this invention, the first protrusion may also have a ring shape extending circumferentially around the central axis. The balloon catheter allows the first protrusion to act on the lesion over a large circumferential range in the distal end connection. Therefore, the balloon catheter can prevent the balloon from moving along the extension direction when the balloon is inflated and the first protrusion is acting on the lesion.

[0017] In this invention, the first protrusion may also have a spiral shape extending circumferentially around the central axis. The balloon catheter allows the first protrusion to act on the lesion over a wide range of circumferential and extending directions in the distal end connection. Therefore, the balloon catheter can prevent the balloon from moving along the extending direction while the first protrusion is acting on the lesion during balloon inflation.

[0018] In this invention, the front connecting portion may also have multiple inclined portions, including at least two inclined portions, wherein the at least two inclined portions have different inclination angles between themselves and the central axis along their respective directions extending from the second front end side toward the third front end side, and the first protrusion is disposed in the inclined portion with the smallest inclination angle among the multiple inclined portions. In this case, the movement direction of the first protrusion, which moves during balloon inflation, is approximately radial. In this case, the balloon catheter allows the first protrusion to properly act on the lesion.

[0019] In this invention, the protrusion may also include a second protrusion. In this case, the balloon catheter can use the second protrusion of the extended tip portion to act on the lesion while advancing the balloon within the blood vessel. In this case, the balloon catheter can advance the balloon even within lesions with small lumens. Furthermore, the second protrusion of the extended tip portion of the balloon catheter can prevent the balloon from being pushed back in the opposite direction of travel when the lesion within the blood vessel is expanded by repeated balloon inflation / contraction.

[0020] In this invention, the second protrusion may also have multiple protrusions, each protruding larger as it approaches the third anterior end. In this case, the balloon catheter can suppress resistance encountered from the lesion during balloon entry. Therefore, the balloon catheter can reduce the situation where the balloon is pushed back in the opposite direction of entry due to resistance encountered from the lesion during balloon entry into the lesion.

[0021] In this invention, the second protrusion may also include: a second apex, which protrudes most outward in the radial direction; a second frontal ramp, which extends from an end near the first frontal portion toward the second apex; and a second base ramp, which extends from an end near the third frontal portion toward the second apex, wherein the angle of the second base ramp relative to the frontal extension is larger than the angle of the second frontal ramp relative to the frontal extension. In this case, the balloon catheter can reduce the possibility of the second protrusion getting caught in the blood vessel and hindering its progress when the balloon is advanced within the blood vessel.

[0022] In this invention, the distal extension portion may also have a region between the end of the protrusion closest to the first distal end and the first distal end, where the protrusion amount is smaller than that of the protrusion itself. In this case, the balloon catheter allows the area where the protrusion is located in the distal extension portion to be smaller than the area where the protrusion is located throughout the entire distal extension portion. Therefore, even with the protrusion, the balloon catheter can still provide good passage of the balloon within the blood vessel. Attached Figure Description

[0023] Figure 1 This is a diagram obtained by observing balloon catheter 1A from the side.

[0024] Figure 2 This is a diagram obtained by observing balloon catheter 1A from the front side.

[0025] Figure 3A This is a diagram illustrating an example of the use of balloon catheter 1A.

[0026] Figure 3BThis is a diagram illustrating an example of the use of balloon catheter 1A.

[0027] Figure 3C This is a diagram illustrating an example of the use of balloon catheter 1A.

[0028] Figure 3D This is a diagram illustrating an example of the use of balloon catheter 1A.

[0029] Figure 3E This is a diagram illustrating an example of the use of balloon catheter 1A.

[0030] Figure 4A This is a diagram illustrating an example of the use of balloon catheter 1A.

[0031] Figure 4B This is a diagram illustrating an example of the use of balloon catheter 1A.

[0032] Figure 4C This is a diagram illustrating an example of the use of balloon catheter 1A.

[0033] Figure 4D This is a diagram illustrating an example of the use of balloon catheter 1A.

[0034] Figure 4E This is a diagram illustrating an example of the use of balloon catheter 1A.

[0035] Figure 5A This is a diagram illustrating an example of the use of balloon catheter 1A.

[0036] Figure 5B This is a diagram illustrating an example of the use of balloon catheter 1A.

[0037] Figure 5C This is a diagram illustrating an example of the use of balloon catheter 1A.

[0038] Figure 5D This is a diagram illustrating an example of the use of balloon catheter 1A.

[0039] Figure 6 The image is an enlarged view of the area near the front connector 3A of the balloon catheter 1B.

[0040] Figure 7 The image is an enlarged view of the area near the front connector 3A of the balloon catheter 1C.

[0041] Figure 8 The image is an enlarged view of the area near the front connector 3A of the balloon catheter 1D.

[0042] Figure 9 The image is an enlarged view of the vicinity of the front end connector 3A of the balloon catheter 1E.

[0043] Figure 10 The image shows the balloon catheter 1F viewed from the side, and the cross-sectional view is obtained by viewing along the arrow direction at line AA.

[0044] Figure 11 This is a diagram showing a modified example of the balloon catheter 1F.

[0045] Figure 12A The figure shows a modified example of protrusions 41G and 42G.

[0046] Figure 12B The figure shows a modified example of protrusions 41G and 42G.

[0047] Figure 12C The figure shows a modified example of protrusions 41G and 42G.

[0048] Figure 13A The diagram shows the protrusion 46G.

[0049] Figure 13B The diagram shows the protrusion 47G.

[0050] Figure 13C This is a diagram showing the protrusion 48G.

[0051] Figure 14 The image is an enlarged view of the vicinity of the front connecting portion 3A of the balloon catheter 1G.

[0052] Figure 15 This is a magnified cross-sectional view of the vicinity of the front end connector 3A of the balloon catheter 1H.

[0053] Figure 16A This is a cross-sectional view showing the cover tube 7B.

[0054] Figure 16B This is a cross-sectional view showing the cover tube 7C.

[0055] Figure 16C This is a cross-sectional view showing the shroud tube 7D. Detailed Implementation

[0056] Embodiments of the balloon catheter 1 of the present invention (balloon catheters 1A to 1H) will be described with reference to the accompanying drawings. The accompanying drawings are used to illustrate the technical features employed in the present invention. The structures of the described devices are not intended to be limited thereto, but are merely illustrative examples. The balloon catheter 1 can dilate stenotic lesions formed in blood vessels using the balloon 3, or apply the protrusions 4 (protrusions 4A to 4E, 4G, 4I, described later) to the blood vessel.

[0057] <First Embodiment (Balloon Catheter 1A)>

[0058] Reference Figure 1 , Figure 2 The balloon catheter 1A is described below. The balloon catheter 1A has a catheter shaft 2, a balloon 3, and protrusions 4A and 4B.

[0059] <Catheter axis 2>

[0060] The catheter shaft 2 is tubular. A balloon 3 is connected near one end of the catheter shaft 2. A catheter hub (not shown) is connected to the other end of the catheter shaft 2. The catheter hub can supply compressed fluid to the balloon 3 via the catheter shaft 2.

[0061] One of the two ends of catheter shaft 2 is called the "front end side". The other end of catheter shaft 2 is called the "base end side". The direction extending along catheter shaft 2 is called the "extension direction". The axis that passes through the center of catheter shaft 2 and extends along the extension direction is called the "central axis C1". In the cross section (hereinafter referred to as the "section") in the case of cutting in a plane orthogonal to the central axis C1, the side closer to the central axis C1 in the radial direction centered on the central axis C1 is called the "inner side", and the side away from the central axis C1 in the radial direction centered on the central axis C1 is called the "outer side".

[0062] The catheter shaft 2 has an outer tube 21 and an inner tube 22. Both the outer tube 21 and the inner tube 22 are flexible. The inner diameter of the outer tube 21 is larger than the outer diameter of the inner tube 22. The inner tube 22, except for a predetermined portion at its anterior end, is disposed within the lumen of the outer tube 21. A predetermined portion at the anterior end of the inner tube 22 protrudes from the anterior end of the outer tube 21 (hereinafter referred to as "anterior portion 211") toward the anterior end. The anterior end of the inner tube 22 (hereinafter referred to as "anterior portion 221") is positioned further anteriorly than the anterior portion 211 of the outer tube 21. Hereinafter, the predetermined portion at the anterior end of the inner tube 22 will be referred to as "protruding portion 225". The basal end of the outer tube 21 will be referred to as "basal end 212". The basal end of the inner tube 22 will be referred to as "basal end 222". A catheter tip is connected to at least the basal end 212 of the outer tube 21. The materials of the outer tube 21 and the inner tube 22 are not particularly limited; as an example, a polyamide resin is used.

[0063] Compressed fluid supplied from the catheter tip flows through the space outside the inner lumen of the inner tube 22, which is located within the inner lumen of the outer tube 21. A guidewire (not shown) is inserted into the inner lumen of the inner tube 22.

[0064] <Balloon 3>

[0065] The balloon 3 is deformable between a contracted and inflated state by varying the internal pressure and the supply of compressed fluid via a catheter tip (not shown). Figure 1 The balloon 3 is shown in its inflated state.

[0066] The front end of the balloon 3 (hereinafter referred to as "front end 3D") is heat-fused to the portion of the protrusion 225 of the inner tube 22 that is closer to the base end than the front end 221. Hereinafter, the portion of the protrusion 225 of the inner tube 22 where the front end 3D of the balloon 3 is connected and the front end 221 are referred to as the "front end extension portion 220". Furthermore, the base end of the balloon 3 (hereinafter referred to as "base end 3P") is heat-fused to the vicinity of the front end 211 of the outer tube 21. The distance between the front end 3D of the balloon 3 and the front end 221 of the inner tube 22 is shorter than the distance between the base end 3P of the balloon 3 and the base end 222 of the inner tube 22. The balloon 3 covers the protrusion 225 of the inner tube 22 from the outside. The material of the balloon 3 is not particularly limited; polyamide resin is used as an example.

[0067] In balloon 3, an anterior connecting portion 3A, an expansion portion 3B, and a basal connecting portion 3C are defined. The anterior connecting portion 3A is the region in balloon 3 in its inflated state that extends in diameter from the anterior end portion 3D toward the basal end portion 3P. The basal connecting portion 3C is the region in balloon 3 in its inflated state that extends in diameter from the basal end portion 3P toward the anterior end portion 3D. The expansion portion 3B is the region in balloon 3 in its inflated state sandwiched between the anterior connecting portion 3A and the basal connecting portion 3C, and has a roughly the same diameter throughout its extension direction. In its inflated state, the expansion portion 3B becomes a cylindrical shape extending in the extension direction. The end portion of the expansion portion 3B near the anterior end portion 221 of the inner tube 22 of the catheter shaft 2, i.e., the anterior end portion, is referred to as the "anterior end portion 30D". The end portion of the expansion portion 3B near the basal end portion 222 of the inner tube 22 of the catheter shaft 2, i.e., the basal end portion, is referred to as the "basal end portion 30P".

[0068] The front connecting portion 3A extends towards the front end 3D from the end connected to the front end 30D of the expansion portion 3B. The diameter of the cross-section of the front connecting portion 3A is largest at the end connected to the front end 30D of the expansion portion 3B and smallest at the front end 3D. The base connecting portion 3C extends towards the base end 3P from the end connected to the base end 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 end 30P of the expansion portion 3B and smallest at the base end 3P.

[0069] <Prominent Part 4A>

[0070] A protrusion 4A is provided on the outer surface of the front connecting portion 3A of the balloon 3 and protrudes outward. The protrusion 4A has protruding bodies 41A and 42A. The protruding bodies 41A and 42A are positioned opposite each other, sandwiching the central axis C1. The protruding bodies 41A and 42A are each conical in shape. The apex 410 of the protruding bodies 41A and 42A protrudes outward the most among the protruding bodies 41A and 42A. The bottom of the protruding bodies 41A and 42A is connected to the outer surface of the front connecting portion 3A of the balloon 3. The protruding bodies 41A and 42A have the same shape. The shortest distance between the bottom surface of each protruding body 41A and 41B and the apex 410 corresponds to the protrusion amount of the protrusion 4A. Hereinafter, the shape of the protrusion 4A will be described by way of example of the protruding body 41A.

[0071] The portion of the bottom of the protrusion 41A closest to the front end 3D of the front connecting portion 3A is called the front end 415. The portion of the side of the protrusion 41A corresponding to the generatrix of the connecting vertex 410 and the front end 415 is called the "front ramp portion 411". The front ramp portion 411 extends from the front end 415 toward the vertex 410 along the side of the protrusion 41A. The portion of the bottom of the protrusion 41A closest to the front end 30D of the expansion portion 3B is called the base end 416. The portion of the side of the protrusion 41A corresponding to the generatrix of the connecting vertex 410 and the base end 416 is called the "base ramp portion 412". The base ramp portion 412 extends from the base end 416 toward the vertex 410 along the side of the protrusion 41A. In this case, the angle θ12 of the base ramp portion 412 relative to the front connecting portion 3A is larger than the angle θ11 of the front ramp portion 411 relative to the front connecting portion 3A (θ11 < θ12).

[0072] The base end portion 416 of each of the protrusions 41A and 42A moves away from the front end portion 30D of the expansion portion 3B of the balloon 3 towards the anterior end. Therefore, in the anterior end connecting portion 3A of the balloon 3, in the extending direction, there is a region W1 where the protrusion 4A is not provided between the portion connecting to the front end portion 30D of the expansion portion 3B and the base end portion 416 of the protrusion 4A. The front end portion 415 of each of the protrusions 41A and 42A moves away from the base end portion 3D of the anterior end connecting portion 3A of the balloon 3. Therefore, in the anterior end connecting portion 3A of the balloon 3, in the extending direction, there is a region W2 where the protrusion 4A is not provided between the front end portion 3D and the front end portion 415 of the protrusion 4A.

[0073] <Prominent part 4B>

[0074] A protrusion 4B is provided on the outer surface of the front end extension portion 220 of the inner tube 22 and protrudes outward. The protrusion 4B has protruding bodies 41B and 42B. The protruding bodies 41B and 42B are positioned opposite each other, sandwiching a central axis C1. The protruding bodies 41B and 42B are each conical in shape. The apex 420 of the protruding bodies 41B and 42B protrudes outward the most among the two. The bottom of the protruding bodies 41B and 42B is connected to the outer surface of the front end extension portion 220. The protruding bodies 41B and 42B have the same shape. The protrusion amount of the protrusion 4B is smaller than that of the protrusion 4A. Hereinafter, the shape of the protrusion 4B will be described by way of example with the protruding body 41B.

[0075] The portion of the bottom of the protrusion 41B closest to the front end 221 of the inner tube 22 is called the front end 425. The portion of the side of the protrusion 41B corresponding to the generatrix connecting the vertex 420 and the front end 425 is called the "front ramp portion 421". The front ramp portion 421 extends from the front end 425 toward the vertex 420 along the side of the protrusion 41B. The portion of the bottom of the protrusion 41B closest to the front end 3D of the front connecting portion 3A of the balloon 3 is called the base end 426. The portion of the side of the protrusion 41B corresponding to the generatrix connecting the vertex 420 and the base end 426 is called the "base ramp portion 422". The base ramp portion 422 extends from the base end 426 toward the vertex 420 along the side of the protrusion 41B. In this case, the angle θ22 of the base slope portion 422 relative to the front extension portion 220 is larger than the angle θ21 of the front slope portion 421 relative to the front extension portion 220 (θ21 < θ22).

[0076] The base end portion 426 of each of the protrusions 41B and 42B moves away from the front end portion 3D of the front end connecting portion 3A of the balloon 3 towards the front end. Therefore, in the front end extension portion 220 of the inner tube 22, there is a region W3 in which the protrusion 4B is not provided between the portion connected to the front end portion 3D of the front end connecting portion 3A of the balloon 3 and the base end portion 426 of the protrusion 4B in the extension direction. The front end portion 425 of each of the protrusions 41B and 42B moves away from the base end portion 221 of the inner tube 22. Therefore, in the front end extension portion 220 of the inner tube 22, there is a region W4 in which the protrusion 4B is not provided between the front end portion 221 and the front end portion 425 of the protrusion 4B in the extension direction.

[0077] <Usage Examples>

[0078] An example of the use of balloon catheter 1A will be described. An example is given of using balloon catheter 1A to dilate a stenotic lesion 90A located on a portion of the inner wall of vessel 9. The lumen at the stenotic lesion 90A is very narrow, with a diameter smaller than that of the balloon 3 in its constricted state.

[0079] Insert guidewire G into vessel 9. Prepare balloon catheter 1A with balloon 3 in the contracted state. Figure 3A As shown, at least the portion of the balloon catheter 1A, including the balloon 3, is positioned within the blood vessel 9. A guidewire G is inserted into the inner cannula 22 of the balloon catheter 1A.

[0080] Next, by manipulating the base of balloon catheter 1A, balloon catheter 1A is pressed into vessel 9 along guidewire G. Balloon catheter 1A is moved distally within vessel 9 towards the stenotic lesion 90A with balloon 3 positioned at the tip in the direction of movement. The distal connector 3A of balloon 3 reaches near the proximal end of the stenotic lesion 90A. Figure 3B As shown, only a portion of the anterior end of the balloon 3's anterior connector 3A enters the proximal end of the lumen of the stenotic lesion 90A. Then, the movement of the balloon catheter 1A toward the distal end ceases.

[0081] Next, as Figure 3C As shown, the supply of compressed fluid to balloon 3 begins, and balloon 3 inflates. The protrusion 4A, located at the front connecting portion 3A, cuts into the inner wall of the stenotic lesion 90A. Balloon 3 expands near its proximal end within the lumen of the stenotic lesion 90A using the front connecting portion 3A. It should be noted that because the front connecting portion 3A expands proximally, a force acting proximally from the stenotic lesion 90A acts on balloon 3 as it inflates. However, because the protrusion 4A cuts into the stenotic lesion 90A, movement of balloon 3 proximally is suppressed. Furthermore, the protrusion 4B hooks into the lumen of the stenotic lesion 90A, thereby suppressing the balloon 3's retraction proximally.

[0082] Next, as Figure 3D As shown, the supplied compressed fluid is removed from balloon 3, and balloon 3 becomes contracted. Then, as... Figure 3E As shown, balloon catheter 1A is moved distally through the manipulation base. The distal connector 3A of balloon 3 is inserted deeper into the lumen from the dilated proximal end of the stenotic lesion 90A. Afterward, the movement of balloon catheter 1A ceases.

[0083] Next, as Figure 4A As shown, the supply of compressed fluid to balloon 3 begins, and balloon 3 inflates. The protrusion 4A located at the front connecting portion 3A cuts into the inner wall of the stenotic lesion 90A. Balloon 3 utilizes the front connecting portion 3A to compress the fluid in the stenotic lesion 90A... Figure 3C , Figure 3D The expanded portion extends to the distal side. Additionally, balloon 3 utilizes the expansion section 3B to expand the stenotic lesion 90A within... Figure 3C , Figure 3DThe balloon 3 expands the enlarged portion. Thus, a larger portion of the lumen of the stenotic lesion 90A is dilated. It should be noted that the protrusion 4A cuts into the stenotic lesion 90A, and the protrusion 4B hooks into the lumen of the stenotic lesion 90A. Therefore, even when a force is applied to the balloon 3 in a proximal direction corresponding to the change in its inflated state, movement of the balloon 3 towards the proximal side is inhibited.

[0084] Next, as Figure 4B As shown, the supplied compressed fluid is removed from the balloon 3, and the balloon 3 becomes contracted.

[0085] Repeat the same steps as described above. Figure 4C , Figure 4D , Figure 4E Thus, balloon 3 of balloon catheter 1A gradually moves distally within the lumen of the stenotic lesion 90A. (As...) Figure 5A , Figure 5B , Figure 5C As shown, the lumen of the stenotic lesion 90A gradually increases in size from near the proximal end towards the distal end. Ultimately, as... Figure 5D As shown, the lumen of the stenotic lesion 90A is dilated by balloon 3 throughout the entire area.

[0086] Next, the base of balloon catheter 1A is manipulated, and balloon catheter 1A is moved proximally. The procedure is completed by withdrawing balloon catheter 1A from vessel 9 outwards.

[0087] <Function and Effects of the First Embodiment>

[0088] The balloon catheter 1A dilates small stenotic lesions 90A by repeatedly changing the balloon 3 between an inflated and deflated state and gradually advancing distally. Here, in the balloon catheter 1A, a protrusion 4A is provided at the distal connecting portion 3A of the balloon 3, and a protrusion 4B is provided at the distal extension portion 220 of the inner tube 22. Even when the balloon 3 is subjected to a force towards the proximal side from the stenotic lesion 90A during balloon 3 inflation, the protrusions 4A and 4B inhibit the balloon 3 from moving proximally. Therefore, by repeatedly changing the balloon 3 between an inflated and deflated state and gradually advancing distally, the balloon catheter 1A can appropriately dilate even small stenotic lesions 90A.

[0089] The distal connecting portion 3A of the balloon 3 includes regions W1 and W2 where no protrusion 4A is provided. Therefore, the size of the region in the distal connecting portion 3A where the protrusion 4A is provided is smaller than the case where the protrusion 4A is provided throughout the entire extending direction of the distal connecting portion 3A. Similarly, the distal extension portion 220 of the inner tube 22 includes regions W3 and W4 where no protrusion 4B is provided. Therefore, the size of the region in the distal extension portion 220 where the protrusion 4B is provided is smaller than the case where the protrusion 4B is provided throughout the entire extending direction of the distal extension portion 220. Therefore, compared to the case where the protrusions 4A and 4B are provided throughout the distal connecting portion 3A and the entire extending portion 220, the balloon catheter 1A allows for better passage of the balloon 3 within the blood vessel 9.

[0090] The balloon catheter 1A allows the protrusion 4A of the distal connecting portion 3A of the balloon 3 to penetrate the stenotic lesion 90A within the blood vessel 9 during the repeated expansion and contraction of the balloon 3. In this case, even if the balloon 3 is subjected to a force proximal to the stenotic lesion 90A during balloon 3 expansion, the retraction of the balloon 3 towards the proximal side can be suppressed. Therefore, the balloon catheter 1A allows the balloon 3 to gradually advance and expand relative to the small stenotic lesion 90A, thus efficiently dilating the small stenotic lesion 90A.

[0091] In the protrusion 4A, the angle θ12 of the base slope portion 412 relative to the anterior connecting portion 3A is larger than the angle θ11 of the anterior slope portion 411 relative to the anterior connecting portion 3A. In this case, the resistance encountered by the protrusion 4A from the stenotic lesion 90A when the balloon 3 enters the lumen of the stenotic lesion 90A can be suppressed. Therefore, the balloon catheter 1A can reduce the situation where the balloon 3 is pushed back proximally due to the resistance encountered from the stenotic lesion 90A during its entry into the stenotic lesion 90A.

[0092] The protrusion 4B of the extension setting 220 of the balloon 3 hooks onto the stenotic lesion 90A when the balloon 3 moves in the vessel 9 in the opposite direction to the entry direction. Therefore, the balloon catheter 1A can use the protrusion 4B of the extension setting 220 to prevent the balloon 3 from being pushed back to the proximal side when the stenotic lesion 90A in the vessel 9 is dilated by repeated inflation / contraction of the balloon 3.

[0093] In the protrusion 4B, the angle θ22 of the base slope portion 422 relative to the front extension portion 220 is larger than the angle θ21 of the front slope portion 421 relative to the front extension portion 220. In this case, the balloon catheter 1A can reduce the situation where the protrusion 4B gets caught on the blood vessel 9 and obstructs the progress when the balloon 3 is advanced within the blood vessel 9.

[0094] <Special Considerations for the First Implementation>

[0095] The shape, number, and arrangement of the protrusions of protrusions 4A and 4B are not limited to the embodiments described above. For example, the number of protrusions of protrusions 4A and 4B may be one or more. Furthermore, if the number of protrusions is three or more, the three or more protrusions may be arranged circumferentially around the central axis C1. The shape of the protrusions of protrusions 4A and 4B may be a pyramid, frustum, truncated cone, or prism. It should be noted that if the protrusions 41A and 42A of protrusion 4A are triangular prisms, one of the side faces may be connected to the front end connecting portion 3A of the balloon 3, and the remaining two side faces may form a front end ramp portion 411 and a base end ramp portion 412, with the intersection of the remaining two side faces forming a vertex 410. Similarly, if the protrusions 41B and 42B of the protrusion 4B are triangular prisms, then either of the sides can be connected to the front end extension portion 220 of the inner tube 22, and the remaining two sides can form a front end ramp portion 421 and a base end ramp portion 422, with the intersection of the remaining two sides forming a vertex 420.

[0096] The multiple protrusions of the protrusion 4A can also be arranged in the extending direction along the front end connecting portion 3A of the balloon 3. For example, when viewing the balloon 3 from the front end, the multiple protrusions can be arranged along multiple imaginary lines extending radially from the central axis C1. In this case, the protrusion amount of each of the multiple protrusions can also be different. For example, the protrusion amount of each of the multiple protrusions can also be determined according to the distance from the central axis C1.

[0097] A first connecting portion can also be provided to connect the protrusions 41A and 41B. A second connecting portion can also be provided to connect the protrusions 42A and 42B. The first and second connecting portions can also protrude outward from the outer surface of the front connecting portion 3A of the balloon 3 and the outer surface of the front extension portion 220 of the inner tube 22, respectively. That is, the protrusions 41A and 41B, and the protrusions 42A and 42B can also be integrated to form a single protrusion.

[0098] The position of the extension direction of the base end portion 416 of the protrusions 41A and 42A of the protrusion 4A can also be consistent with the portion that connects to the front end portion 30D of the front end portion 3A and the expansion portion 3B. Alternatively, the position of the extension direction of the front end portion 415 of the protrusions 41A and 42A of the protrusion 4A can also be consistent with the front end portion 3D of the front end portion 3A.

[0099] The protrusions 41B and 42B of the protrusion 4B can also be provided over the entire range of the portion connecting the front end 221 of the inner tube 22 in the front extension section 220 to the front end 3D of the front connecting section 3A. The position of the front end 425 of each of the protrusions 41B and 42B can also coincide with the position of the front end 221 of the inner tube 22. The base end 426 of each of the protrusions 41B and 42B can also coincide with the position of the front end 3D of the front connecting section 3A. That is, the protrusion 4B can be provided over the entire area in the extension direction of the front extension section 220 of the inner tube 22. In this case, there may be no areas W3 and W4 in the front extension section 220 of the inner tube 22 where the protrusion 4B is not provided in the extension direction.

[0100] The balloon catheter 1A may also have only one of the protrusions 4A and 4B. For example, the balloon catheter 1A may have only the protrusion 4A and not the protrusion 4B. Alternatively, the balloon catheter 1A may have only the protrusion 4B and not the protrusion 4A.

[0101] In protrusion 4A, the angle θ11 of the front ramp 411 relative to the front connecting portion 3A and the angle θ12 of the base ramp 412 relative to the front connecting portion 3A can be the same, and angle θ11 can be larger than angle θ21. Either angle θ11 or angle θ12 can be orthogonal to the front connecting portion 3A. In protrusion 4B, the angle θ21 of the front ramp 421 relative to the front extension portion 220 and the angle θ22 of the base ramp 422 relative to the front extension portion 220 can be the same, and angle θ21 can be larger than angle θ22. Either angle θ21 or angle θ22 can be orthogonal to the front extension portion 220.

[0102] In the regions W1 and W2 of the front end connecting portion 3A of the balloon 3, a first protrusion with a smaller protrusion amount than that of the protrusion 4A may also be provided. Additionally, in the regions W3 and W4 of the front end extension portion 220, a second protrusion with a smaller protrusion amount than that of the protrusion 4B may also be provided. The ratio of the protrusion amount of the first protrusion to that of the protrusion 4A and the ratio of the protrusion amount of the second protrusion to that of the protrusion 4B are not particularly limited, but as an example, they are 50% or less, more preferably 10% or less.

[0103] When the balloon catheter 1A has only the protrusion 4B and is provided with the first protrusion, the first protrusion may also be provided in the entire area between the portion of the balloon 3's front end 30D connected to the expansion portion 3B and the front end 3D in the front connecting portion 3A. In addition, the amount of protrusion of the first protrusion may be smaller than the amount of protrusion of the protrusion 4B.

[0104] When the balloon catheter 1A has only the protrusion 4A and is provided with a second protrusion, the second protrusion may also be provided in the entire area between the portion of the front end portion 3D of the balloon 3 and the front end portion 221 in the front extension portion 220. In addition, the amount of protrusion of the second protrusion may be smaller than the amount of protrusion of the protrusion 4A.

[0105] <Second Embodiment (Balloon Catheter 1B)>

[0106] Reference Figure 6 The balloon catheter 1B will be described below. The balloon catheter 1B differs from the balloon catheter 1A in that it lacks the protrusion 4B and has a protrusion 4C instead of the protrusion 4A. Hereinafter, descriptions of structures in the balloon catheter 1B that are identical to those in the balloon catheter 1A will be omitted.

[0107] The protrusion 4C has 41C and 42C, and 41C and 42C have the same shape as the protrusions 41A and 41B of the protrusion 4A. The protrusions 41C and 42C are provided in the portion including the front end portion 3D of the outer surface of the front end connecting portion 3A of the balloon 3. In this case, a portion of the front end side of each of the protrusions 41C and 42C is provided on the outer surface of the front end extension portion 220 of the inner tube 22, and a portion of the base end side of each of the protrusions 41C and 42C is provided on the outer surface of the front end connecting portion 3A of the balloon 3. In addition, the front end portion 415 of each of the protrusions 41C and 42C is located at a position closer to the front end portion 3D of the front end connecting portion 3A of the balloon 3, and the base end portion 416 of each of the protrusions 41C and 42C is located at a position closer to the base end portion 3D of the front end connecting portion 3A of the balloon 3.

[0108] <Function and Effects of the Second Embodiment>

[0109] With the balloon catheter 1B inserted into the stenotic lesion 90A within the blood vessel 9 at the anterior end 3D of the balloon 3, the balloon 3 inflates, dilating the stenotic lesion 90A. In this situation, even if the area of ​​the balloon catheter 1B entering the stenotic lesion 90A is very small, the protrusion 4C can prevent the balloon 3 from being pushed back in the opposite direction of travel. Therefore, even if the stenotic lesion 90A is stiff and it is difficult to insert the anterior end 3A of the constricted balloon 3 into the lumen, the balloon catheter 1B can dilate the stenotic lesion 90A by repeatedly inflating and contracting the balloon 3.

[0110] <Special Considerations for the Second Implementation>

[0111] Alternatively, in addition to the protrusion 4C, the protrusion 4A of the first embodiment may also be provided in the front connecting portion 3A. Alternatively, in addition to the protrusion 4C, the protrusion 4B of the first embodiment may also be provided in the front extending portion 220.

[0112] <Third Embodiment (Balloon Catheter 1C)>

[0113] Reference Figure 7 The balloon catheter 1C will be described below. The balloon catheter 1C differs from the balloon catheter 1A in that it lacks the protrusion 4B and has a protrusion 4D instead of the protrusion 4A. Hereinafter, descriptions of structures in the balloon catheter 1C that are identical to those in the balloon catheter 1A will be omitted.

[0114] The protrusion 4D has protrusions 41D, 42D, and 43D. Protrusions 41D to 43D are disposed on the outer surface of the front connecting portion 3A of the balloon 3 and protrude outward. Each of the protrusions 41D to 43D has a ring shape extending circumferentially around the central axis C1. The protrusions 41D, 42D, and 43D are arranged in this order toward the front end. The diameter of each of the protrusions 41D, 42D, and 43D around the central axis C1 gradually decreases in the order of protrusions 41D, 42D, and 43D.

[0115] The protrusions 41D to 43D each have a planar front end slope portion 431 and a base end slope portion 432 extending outward from the outer surface of the front end connecting portion 3A. Hereinafter, the protrusion 42D will be used as an example for explanation.

[0116] In the protrusion 42D, the portion of the part connected to the front end connector 3A that is near the front end portion 3D of the front end connector 3A is referred to as the front end portion 435. The front end ramp portion 431 extends obliquely from the front end portion 435 toward the base end side relative to the radial direction. In the protrusion 42D, the portion of the part connected to the front end connector 3A that is near the front end portion 30D of the expansion portion 3B is referred to as the base end portion 436. The base end ramp portion 432 extends obliquely from the base end portion 436 toward the front end side relative to the radial direction. The end portion of the front end ramp portion 431 opposite to the front end portion 435 and the end portion of the base end ramp portion 432 opposite to the base end portion 436 are connected at the apex 430. The angle θ32 of the base end ramp portion 432 relative to the front end connector 3A is larger than the angle θ31 of the front end ramp portion 431 relative to the front end connector 3A.

[0117] <Function and Effects of the Third Implementation Method>

[0118] The balloon catheter 1C allows the protrusion 4D to cut into the stenotic lesion 90A over a large circumferential range in the anterior connecting portion 3A. Therefore, the balloon catheter 1C can utilize the protrusion 4D to prevent the balloon 3 from moving in the opposite direction to the direction of entry relative to the stenotic lesion 90A during balloon 3 inflation.

[0119] <Special Considerations for the Third Implementation>

[0120] The number and shape of the protrusions 4D are not limited to the embodiments described above. For example, the apex 430 of each of the protrusions 41D to 43D may also be curved outward in a convex shape. An annular protrusion extending circumferentially around the central axis C1 may also be provided at the front end extension portion 220 of the inner tube 22. A connecting portion connecting the protrusions 41D to 43D may also extend along the outer surface of the front end connecting portion 3A in the extending direction.

[0121] <Fourth Embodiment (Balloon Catheter 1D)>

[0122] Reference Figure 8 The balloon catheter 1D will be described below. The balloon catheter 1D differs from the balloon catheter 1C in that it has a protrusion 4E instead of a protrusion 4D. Hereinafter, descriptions of structures in the balloon catheter 1D that are identical to those in the balloon catheter 1C will be omitted.

[0123] A protrusion 4E is provided on the outer surface of the front connecting portion 3A of the balloon 3 and protrudes outward. The protrusion 4E has a spiral shape extending circumferentially around the central axis C1. The end portion 447 on the base side of the protrusion 4E is located near the front end relative to the front end portion 30D of the inflatable portion 3B of the balloon 3. The end portion 448 on the front end side of the protrusion 4E is located near the base side relative to the front end portion 3D of the front connecting portion 3A.

[0124] In the protrusion 4E, the portion of the part connected to the front end connector 3A that is close to the front end portion 3D of the front end connector 3A is called the front end portion 445. The planar portion extending from the front end portion 445 obliquely toward the base end side with respect to the radial direction is called the front end ramp portion 441. In the protrusion 4E, the portion of the part connected to the front end connector 3A that is close to the front end portion 30D of the expansion portion 3B is called the base end portion 446. The planar portion extending from the base end portion 446 obliquely toward the front end side with respect to the radial direction is called the base end ramp portion 442. The end portion of the front end ramp portion 441 opposite to the front end portion 445 and the end portion of the base end ramp portion 442 opposite to the base end portion 446 are connected at the apex 440. The angle θ42 of the base end ramp portion 442 relative to the front end connector 3A is larger than the angle θ41 of the front end ramp portion 441 relative to the front end connector 3A.

[0125] <Function and Effects of the Fourth Implementation Method>

[0126] The balloon catheter 1D allows the protrusion 4E to act on the stenotic lesion 90A over a wide range of circumferential and extensional directions at the distal connector 3A. Therefore, the balloon catheter 1D can utilize the protrusion 4E to prevent the balloon 3 from moving in the opposite direction to the insertion direction relative to the stenotic lesion 90A during balloon 3 inflation.

[0127] <Special Considerations for the Fourth Implementation>

[0128] The shape of the protrusion 4E is not limited to the above embodiment. For example, the apex 440 of the protrusion 4E may also be curved outward in a convex shape. A spiral protrusion extending circumferentially around the central axis C1 may also be provided at the front end extension portion 220 of the inner tube 22.

[0129] <Fifth Embodiment (Balloon Catheter 1E)>

[0130] Reference Figure 9 The balloon catheter 1E will be described below. The balloon catheter 1E differs from the balloon catheter 1A in that the protrusion 4B is not provided in the tip extension portion 220. Furthermore, the shape of the tip connection portion 3A of the balloon 3 differs from that of the balloon catheter 1A. Hereinafter, descriptions of structures in the balloon catheter 1E that are identical to those in the balloon catheter 1A will be omitted.

[0131] The front end connecting portion 3A of the balloon 3 has inclined portions 36, 37, and 38. In the inflated state, the inclined portion 36 extends from the front end portion 3D of the front end connecting portion 3A toward the base side while expanding in diameter. The inclined portion 37 extends from the end of the inclined portion 36 on the side opposite to the end connected to the front end portion 3D in the extending direction toward the base side while expanding in diameter. The inclined portion 38 extends from the end of the inclined portion 37 on the side opposite to the end connected to the inclined portion 36 in the extending direction toward the base side while expanding in diameter.

[0132] Regarding the inclined portions 36 to 38, the angle between the direction extending from the end near the front end 3D toward the end near the front end 30D and the extending direction is defined as the inclination angle. The inclination angle of inclined portion 36 is denoted as θ51, the inclination angle of inclined portion 37 as θ52, and the inclination angle of inclined portion 38 as θ53. In this case, the inclination angles θ51, θ52, and θ53 are all different. The inclination angles θ51 to θ53 have a magnitude relationship of θ52 < θ51 < θ53. The inclination angle θ53 is the largest, and the inclination angle θ52 is the smallest.

[0133] The protrusions 41A and 42A of the protrusion 4A have the same shape as the balloon catheter 1A. The protrusions 41A and 42A are provided in the inclined section 37 of the inclined section 36 to 38, which has the smallest inclined angle θ52.

[0134] An imaginary surface S0 is defined that connects the front end portion 30D of the inflatable portion 3B of the balloon 3 to the front end portion 3D of the balloon 3. In this case, the protrusions 41A and 41B are located on the side closer to the central axis C1 relative to the imaginary surface S0, that is, on the inside side relative to the imaginary surface S0.

[0135] <Function and Effects of the Fifth Implementation Method>

[0136] During balloon 3 inflation, the inclined portions 36-38 of the anterior connecting portion 3A move in directions orthogonal to each other. Here, the direction of movement of the inclined portion 37, with a relatively smaller inclination angle θ52, is more radial than that of the inclined portions 36 and 38, with relatively larger inclination angles θ51-θ53. It should be noted that the closer the direction of movement of the protrusion 4A during balloon 3 inflation is to radial, the easier it is for the protrusion 4A to cut into the stenotic lesion 90A of blood vessel 9.

[0137] In the balloon catheter 1E, a protrusion 4A is provided in the inclined portion 37 with a relatively small inclination angle θ52. When the balloon 3 is inflated, the protrusion 4A moves in a direction orthogonal to the inclined portion 37. It should be noted that the inclination angle θ52 is defined as the angle of the inclined portion 37 relative to the extension direction; therefore, when the inclination angle θ52 is small, the angle between the direction orthogonal to the inclined portion 37 (i.e., the direction of movement of the protrusion 4A during balloon 3 inflatation) and the radial direction orthogonal to the extension direction is also small. That is, the protrusion 4A moves in an approximately radial direction during balloon 3 inflatation. Therefore, the balloon catheter 1E can allow the protrusion 4A to properly cut into the stenotic lesion 90A during balloon 3 inflatation.

[0138] <Special Considerations for the Fifth Implementation>

[0139] The shape of the protrusion 4A provided on the inclined portion 37 is not limited to the above-described embodiments. For example, the protrusion may also be the shape of the protrusion 4D in the third embodiment (ring-shaped) or the shape of the protrusion 4E in the fourth embodiment (spiral-shaped). The inclination angles θ51 and θ53 may also be the same. The number of inclined portions of the front end connecting portion 3A is not limited to three; it may be two or more. When there are three or more inclined portions, protrusions may be provided on multiple inclined portions with inclination angles smaller than a predetermined threshold. The protrusion 4A may also protrude outward relative to the imaginary surface S0.

[0140] <Sixth Embodiment (Balloon Catheter 1F)>

[0141] Reference Figure 10 The balloon catheter 1F will be described below. The balloon catheter 1F differs from the balloon catheter 1A in that it has protrusions 4G and 4H in addition to protrusion 4A, but does not have protrusion 4B. Hereinafter, descriptions of structures in the balloon catheter 1F that are identical to those in the balloon catheter 1A will be omitted.

[0142] A protrusion 4G is provided on the outer surface of the expansion portion 3B of the balloon 3 and protrudes outward. The protrusion 4G has protruding bodies 41G and 42G. Protruding bodies 41G and 42G extend along the extension direction over the entire range between the front end portion 30D and the base end portion 30P of the expansion portion 3B. Protruding bodies 41G and 42G are positioned opposite each other about the central axis C1. The circumferential positions of protruding bodies 41G and 42G are consistent. The circumferential positions of protruding bodies 42G are also consistent.

[0143] The protrusions 41G and 42G have the same shape. The shape of protrusion 41G will be described below using it as an example. Protrusion 41G has a base portion 51 and a front portion 52. The base portion 51 is a quadrangular prism and extends in the extending direction. The side surface 51A of the base portion 51 is connected to the outer surface of the expansion portion 3B of the balloon 3. The front portion 52 is a triangular prism and extends in the extending direction. The side surface 52A of the front portion 52 is connected to the side surface 51B of the base portion 51, which is opposite to side surface 51A. The sides 52B and 52C of the front portion 52, other than side surface 52A, are connected at the vertex 520. The distance between the sides 51A and 51B of the base portion 51 is equal to the distance between the side surface 52A of the front portion 52 and the vertex 520.

[0144] In the cross-section of the protrusion 41G, two ends 510 in the side surface 51A are defined in a direction orthogonal to the extending direction. Additionally, two imaginary line segments S1 are defined connecting the two ends 510 to the vertex 520, respectively. In this case, a portion of the base portion 51 and a portion of the front end portion 52 of the protrusion 41G are positioned outwards relative to an imaginary triangle (hereinafter referred to as "imaginary triangle T1") defined by the two imaginary line segments S1 and the side surface 51A.

[0145] A protrusion 4H is disposed on the inner surface of the front connecting portion 3A of the balloon 3 and protrudes inward. The protrusion 4H has protruding bodies 41H and 42H. Protruding body 41H extends over the entire range between the front end of protruding body 41G and protruding body 41A. Protruding body 42H extends over the entire range between the front end of protruding body 42G and protruding body 42A. The protrusion 4H is sandwiched between protrusions 4A and 4G and connects protrusions 4A and 4G on the inner side of the balloon 3.

[0146] <Function and Effects of the Sixth Implementation Method>

[0147] In the balloon catheter 1F, the rigidity of the portion of balloon 3 with the protrusion 4H is made equal to the rigidity of the portion of balloon 3 with the protrusion 4A. Therefore, the protrusion 4H can be used to prevent the protrusion 4A from being pushed back towards the central axis C1 due to stress from the stenotic lesion 90A during balloon 3 inflation. The protrusion 4H protrudes inward from the inner surface of the front connecting portion 3A of balloon 3, and not outward from the outer surface. Therefore, the balloon catheter 1F can suppress the reduction in the permeability of balloon 3 caused by the protrusion 4H.

[0148] When the balloon 3 contracts, an inward force is applied to the portion of the balloon 3 where the protrusion 4H is located. In this case, a blade is easily formed during the contraction of the balloon 3. It should be noted that the balloon 3 minimizes its diameter in the contracted state by folding the blade formed in the contracted state. Therefore, the balloon catheter 1F can appropriately form a blade within the balloon 3 in the contracted state using the protrusion 4H, thus reducing the diameter of the balloon 3 in the contracted state.

[0149] In the cross-sections of the protrusions 41G and 42G of the protrusion 4G, a portion of the base portion 51 and a portion of the anterior portion 52 are respectively positioned laterally relative to the imaginary triangle T1. Therefore, the protrusions 41G and 42G are difficult to tip over even when subjected to external force. Thus, the balloon catheter 1F can, during the inflation of the balloon 3, allow both the protrusion 4A and the protrusion 4G to act on the stenotic lesion 90A, thereby enabling appropriate treatment of the stenotic lesion 90A.

[0150] <Special Considerations for the Sixth Implementation Method>

[0151] Regarding the portion of the front connecting part 3A of the balloon 3 where the protrusion 4H is provided on the inner surface, a third protrusion protruding outward may also be provided on the outer surface. It should be noted that the amount of protrusion of the third protrusion is smaller than the amount of protrusion of the protrusion 4A. The ratio of the amount of protrusion of the third protrusion to the amount of protrusion of the protrusion 4A is not particularly limited, but as an example, it is 50% or less, and more preferably 10% or less.

[0152] like Figure 11 As shown, the protrusion 4H may also extend over the entire range between the end of the protrusion 4G on the front end side and the front end portion 3D of the balloon 3. In this case, the protrusion 4H may also be provided over the entire range between the end of the protrusion 4G on the front end side and the front end portion 3D of the balloon 3 on the inner surface of the front end connecting portion 3A of the balloon 3.

[0153] The protrusion 4G may also be provided on the inner surface of the expansion portion 3B of the balloon 3 and protrude inward. The protrusion 4G may also be formed in a ring shape along the circumference centered on the central axis C1. In this case, the protrusion 4G may also be formed only near the front end portion 30D of the expansion portion 3B of the balloon 3.

[0154] The protrusion 4H can also be provided in the entire area of ​​the inner surface of the front end connecting portion 3A of the balloon 3, which is closer to the base end side than the protrusion 4A in the extending direction.

[0155] The hardness of the protrusions 41G and 42G in protrusion 4G can be uniform throughout the entire area, or it can vary for each part. For example... Figure 12A As shown, the hardness of each of the protrusions 41G and 42G gradually increases from the side 51A towards the apex 520. In this case, the area near the apex 520 of the protrusions 41G and 42G is particularly difficult to tilt even with external force, thus allowing the protrusion 4G to properly cut into the stenotic lesion 90A when the balloon 3 is inflated. Furthermore, the area near the portion of the protrusions 41G and 42G that connects to the balloon 3 can maintain flexibility. Therefore, the possibility of the protrusion 4G getting caught on the inner wall and reducing its passage when the balloon 3 passes through the blood vessel 9 can be reduced.

[0156] For example, Figure 12B As shown, for the protrusions 41G and 42G, an imaginary center S2 is defined as an imaginary line segment extending radially from the vertex 520. For the base portion 51 of each of the protrusions 41G and 42G, side surfaces 51C and 51D are defined, excluding side surfaces 51A and 51B. In this case, the hardness of each of the protrusions 41G and 42G can gradually increase from the side surfaces 51C, 51D, 52B, and 51C towards the imaginary center S2. Furthermore, for example... Figure 12C As shown, in the cross-sections of protrusions 41G and 42G, the hardness of the portion disposed on the inner side relative to the imaginary triangle T1 can be higher than the hardness of the portion disposed on the outer side relative to the imaginary triangle T1.

[0157] exist Figure 12B , Figure 12C In the example shown, the protrusion 4G is stably positioned on the outer surface of the balloon 3, making it difficult to tip over even under external force. Therefore, the protrusion 4G can be properly inserted into the stenotic lesion 90A when the balloon 3 is inflated.

[0158] The shape of the protrusion 4G is not limited to the above embodiment. A variation related to the shape of the protrusions 41G and 42G of the protrusion 4G (protrusion 46G (see reference)) is also possible. Figure 13A ), 47G (refer to Figure 13B ), 48G (reference) Figure 13C The following explanation will be provided. The direction extending radially from the central axis C1 of the balloon 3 through the vertex 520 will be referred to as the "protrusion direction". The direction orthogonal to both the extension direction and the protrusion direction will be referred to as the "orthogonal direction".

[0159] Figure 13A The protrusion 46G shown has base elements 511 and 512 as a base portion 51. Each of the base elements 511 and 512 is a quadrangular prism and extends along the extending direction. The side surface 512A of the base element 512 is connected to the expansion portion 3B of the balloon 3. The side surface 511A of the base element 511 is connected to the side surface 512B of the base element 512 opposite to side surface 512A. The side surface 52A of the front end portion 52 is connected to the side surface 511B of the base element 511 opposite to side surface 511A.

[0160] The length of the base element 511 in the orthogonal direction is shorter than the length of the base element 512 in the orthogonal direction. The length of the side surface 52A of the front end portion 52 is shorter than the length of the base element 511 in the orthogonal direction. In the cross-section of the protrusion 46G, portions of the two ends of the base elements 511, 512, and the front end portion 52, including those in the orthogonal direction, are positioned outward relative to the imaginary triangle T1. The length of the base portion 51 in the protruding direction is longer than the length of the front end portion 52 in the protruding direction.

[0161] The protrusion 46G can stably support the anterior end 52 using the base portion 51. Therefore, the anterior end 52 of the protrusion 46G can properly cut into the stenotic lesion 90A when the balloon 3 is inflated.

[0162] Figure 13B The shape of the base element 512 of the protrusion 47G shown is the same as that of the protrusion 46G (see reference). Figure 13A The base element 512 is a trapezoidal prism. The side surface 512B of the base element 512 is shorter than the side surface 512A. It should be noted that side surface 512B is longer than the side surface 511A of the base element 511.

[0163] Define the sides 512C and 512D of the base element 512, excluding sides 512A and 512B. The direction extending along sides 512C and 512D from side 512A towards side 512B is inclined towards the imaginary center S2 passing through vertex 520. In the cross-section of the protrusion 47G, portions of the two ends of the base elements 511 and 512, including those in orthogonal directions, are positioned outward relative to the imaginary triangle T1.

[0164] Figure 13C The shape of the base element 511 of the protrusion 48G shown is the same as that of the protrusion 47G (see reference). Figure 13BThe base element 511 is a trapezoidal prism. The side surface 511B of the base element 511 is shorter than the side surface 511A. It should be noted that side surface 511B is longer than the side surface 52A of the front end 52.

[0165] Define the sides 511C and 511D of the base element 511, excluding sides 511A and 511B. The direction extending along sides 511C and 511D from side 511A towards side 511B is inclined towards the imaginary center S2 passing through vertex 520. In the cross-section of the protrusion 48G, portions of the two ends of the base elements 511, 512, and front end 52, including those in orthogonal directions, are positioned outward relative to the imaginary triangle T1.

[0166] In the protrusions 47G and 48G, the base portion 51 can further stably support the anterior portion 52. Therefore, when the balloon 3 is inflated, the anterior portions 52 of the protrusions 47G and 48G can appropriately act on the stenotic lesion 90A. In addition, the steps on the orthogonal side of the protrusions 47G and 48G can be reduced, so even if the protrusion amount of the protrusions 47G and 48G is increased, it is difficult for them to tip over. Therefore, by increasing the protrusion amount of the protrusions 47G and 48G, the protrusions 47G and 48G can be appropriately inserted into the stenotic lesion 90A when the balloon 3 is inflated.

[0167] <Seventh Embodiment (Balloon Catheter 1G)>

[0168] Reference Figure 14 The balloon catheter 1G will be described below. The balloon catheter 1G differs from the balloon catheter 1A in that it lacks the protrusion 4A and has a protrusion 4I instead of the protrusion 4B. Hereinafter, descriptions of structures in the balloon catheter 1G that are identical to those in the balloon catheter 1A will be omitted.

[0169] The protrusion 4I has protrusions 41I, 42I, 43I, 44I, 45I, and 46I. Protrusions 41I to 46I are disposed on the outer surface of the front end extension portion 220 of the inner tube 22 and protrude outwards. Protrusions 41I, 42I, and 43I are arranged along the extension direction. The circumferential positions of protrusions 41I, 42I, and 43I are consistent. Protrusions 44I, 45I, and 46I are arranged along the extension direction. The circumferential positions of protrusions 44I, 45I, and 46I are consistent. Protrusions 41I and 44I are close to the anterior end portion 30D of the balloon 3. Protrusions 43I and 46I are close to the anterior end portion 221 of the inner tube 22. Protrusions 41I and 44I are opposite each other about the central axis C1. Protrusions 42I and 45I are opposite each other about the central axis C1. Protrusions 41I and 44I are positioned opposite each other with the central axis C1 as the center.

[0170] The shape of protrusions 41I to 46I is similar to that of balloon catheter 1A (see reference). Figure 1 The protrusions 41B and 42B of the protrusion 4B in the diagram have similar shapes. The front end portion 465, base end portion 466, front end slope portion 461, base end slope portion 462, apex 460, angles θ61 and θ62 of each of the protrusions 41I to 46I correspond to the front end portion 425, base end portion 426, front end slope portion 421, base end slope portion 422, apex 420, angles θ21 and θ22 of each of the protrusions 41B and 42B of the protrusion 4B, respectively. The angle θ62 of the base end slope portion 462 relative to the front end extension portion 220 is larger than the angle θ61 of the front end slope portion 461 relative to the front end extension portion 220.

[0171] The distances (i.e., protrusion amounts) from the front end portion 220 to the apex 460 of each of the protrusions 41I, 42I, and 43I are different. Among the protrusions 41I, 42I, and 43I, the protrusion amount of protrusion 43I, which is closest to the front end portion 221 of the inner tube 22, is the smallest, and the protrusion amount of protrusion 41I, which is closest to the front end portion 3D of the balloon 3, is the largest. The closer the protrusions 41I, 42I, and 43I are to the front end portion 3D of the balloon 3, the larger their respective protrusion amounts.

[0172] The protrusion amounts of protrusions 44I, 45I, and 46I are different. Among protrusions 44I, 45I, and 46I, the protrusion amount of protrusion 46I, which is closest to the anterior end 221 of the inner tube 22, is the smallest, and the protrusion amount of protrusion 44I, which is closest to the anterior end 3D of the balloon 3, is the largest. The closer the protrusion amount of each of the protrusions 44I, 45I, and 46I is to the anterior end 3D of the balloon 3, the larger it is.

[0173] <Function and Effects of the Seventh Implementation Method>

[0174] In the balloon catheter 1G, the resistance encountered by the protrusion 4I from the stenotic lesion 90A during the advancement of the protrusion 220 of the inner tube 22 into the lumen of the stenotic lesion 90A can be suppressed. Therefore, the balloon catheter 1G can reduce the possibility of the balloon 3 being pushed back due to the resistance encountered by the protrusion 4I from the stenotic lesion 90A.

[0175] The balloon catheter 1G has protrusions 41I-43I and 44I-46I arranged in the extension direction. Therefore, compared with the case of balloon catheter 1A which only has protrusions 41A and 41B, the distal extension portion 220 of the inner tube 22 is less likely to be pushed back when encountering resistance from the stenotic lesion 90A during its advancement within the lumen of the stenotic lesion 90A. Therefore, the balloon catheter 1G can more efficiently and effectively perform the action of repeatedly changing the balloon 3 between an inflated and contracted state and gradually advancing distally.

[0176] <Special Considerations for the Seventh Implementation Method>

[0177] The protrusion amounts of protrusions 41I to 46I can also be the same. Alternatively, the protrusion amounts of protrusions 42I, 43I, 45I, and 46I can be set to be the same, and the protrusion amounts of protrusions 41I and 44I can be smaller than those of protrusions 42I, 43I, 45I, and 46I. The circumferential positions of each of the protrusions 41I to 43I can also be different. Similarly, the circumferential positions of each of the protrusions 44I to 46I can also be different. The balloon catheter 1G can also have a protrusion 4A at the anterior connecting portion 3A of the balloon 3.

[0178] <Eighth Implementation Method>

[0179] Reference Figure 15 The balloon catheter 1H is described below. The balloon catheter 1H differs from the balloon catheter 1A in that the balloon 3 has an anterior junction 3J, has only a protrusion 4A but not a protrusion 4B, and also has an anterior lip 6A and a sheath 7A (see reference). Figure 1 They are different. The following descriptions of structures in balloon catheter 1H that are identical to those in balloon catheter 1A will be omitted.

[0180] The balloon 3 of the balloon catheter 1H has a front end joint 3J extending from the front end portion 3D of the front end connection portion 3A toward the front end side. The front end joint 3J extends along the outer surface of the inner tube 22 and engages with the inner tube 22. Hereinafter, the front end of the front end joint 3J will be referred to as the "front end portion 300D".

[0181] A front lip 6A is provided at the front end 221 of the inner tube 22. The front lip 6A is made of soft resin. The front lip 6A prevents the blood vessel 9 from being injured when the front end 221 of the inner tube 22 collides with the inner wall of the blood vessel 9.

[0182] The anterior lip 6A has a covering portion 61 and an extension portion 62. The covering portion 61 covers the front end portion 221 of the inner tube 22 from the anterior end side. A through hole 61A is provided in the covering portion 61 for a guide wire inserted into the inner tube 22 to pass through. The diameter of the through hole 61A is smaller than the diameter of the inner cavity of the inner tube 22. The extension portion 62 extends from the outer end of the covering portion 61 along the outer surface of the inner tube 22 towards the base end side. The base end end of the extension portion 62 (hereinafter referred to as "base end portion 62P") moves away from the anterior end portion 300D of the anterior end joint portion 3J of the balloon 3 towards the anterior end side. The portion of the inner tube 22 that is closer to the base end portion 62P and closer to the anterior end portion 300D in the extending direction is not covered by the anterior lip 6A and the anterior end joint portion 3J. Hereinafter, the portion of the inner tube 22 that is not covered by the anterior lip 6A and the anterior end joint portion 3J will be referred to as "exposed portion 226".

[0183] The cover tube 7A is cylindrical. The cover tube 7A covers the portion near the base end 62P of the extension 62 of the front end lip 6A, the portion near the front end 300D of the front end joint 3J of the balloon 3, and the exposed portion 226 of the inner tube 22 from the outside. The cover tube 7A has uniform hardness.

[0184] The canopy 7A, the anterior lip 6A, and the balloon 3 are melted by heat. For the balloon catheter 1H, in... Figure 15 Heat is applied near the front end in the state shown. As a result, the portion near the base end 62P of the extension 62 of the cover tube 7A, the portion near the front end 300D of the front end joint 3J of the balloon 3 melts and fuses with each other. Therefore, for in Figure 15 Regarding the steps present in the near portion of the base end 62P of the extension 62 of the front lip 6A and the near portion of the front end 300D of the front end joint 3J of the balloon 3, the steps are eliminated by the molten shroud 7A entering the stepped portion due to heating. (The following will be discussed further.) Figure 16A , 16B The same applies to 16C.

[0185] <Function and Effects of the Eighth Implementation Method>

[0186] Without the sheath 7A, the hardness of the portion of the balloon catheter 1H closer to the anterior end 3D of the balloon 3 differs in the following directions: region W6 closer to the anterior end 62P, region W7 between the base end 62P and the anterior end 300D, and region W8 closer to the base end 300D. Region W7 is softer than regions W6 and W8. This is because region W6 has an inner tube 22 and an anterior lip 6A, region W8 has an inner tube 22 and an anterior junction 3J, while region W7 only has an inner tube 22. Here, to ensure good guidewire followability, it is preferable that the difference in hardness between regions W6 and W8 is small.

[0187] In contrast, in the balloon catheter 1H, a canopy 7A is provided at the position overlapping with region W7. Region W7 is harder than region W6, and region W8 is harder than region W7 (hardness of region W6 < hardness of region W7 < hardness of region W8). By using the canopy 7A to harden region W7, the hardness difference between regions W6, W8, and W7 can be reduced. Therefore, the balloon catheter 1H allows for good guidewire following at its tip.

[0188] <Special Considerations for the Eighth Implementation>

[0189] For example, 7B, a modified version of the shroud ( Figure 16A ), 7C ( Figure 16B ), 7D Figure 16C (This will be explained.)

[0190] Figure 16A The difference between the shown cover tube 7B and cover tube 7A is that a portion of the diameter of the outer surface tends to expand towards the base end, and the end of the front end side of cover tube 7B is located inside the extension 62 of the front end lip 6A. It should be noted that the end of the base end side of cover tube 7B is located outside the front end joint 3J of balloon 3, just like cover tube 7A, and covers the vicinity of the front end portion 300D of the front end joint 3J from the outside.

[0191] Figure 16B The difference between the cover tube 7C and the cover tube 7A is that the end of the front end side of the cover tube 7C is located inside the extension 62 of the front end lip 6A, and the end of the base end side of the cover tube 7C is located inside the front end joint 3J. In this case, the cover tube 7C extends along the outer surface of the inner tube 22 in the extending direction throughout the entire region.

[0192] Figure 16C The difference between the canopy 7D and the canopy 7A is the non-uniformity of hardness. The hardness of the canopy 7D is higher in the region corresponding to W7 than in the regions corresponding to W6 and W8. This allows for a smaller difference in hardness between regions W6 to W8 within the balloon catheter 1H, thus improving the follow-through of the guidewire at the tip. It should be noted that the canopy 7D can also be constructed from different materials for regions W6 to W8, which have different hardness levels. Alternatively, the hardness of the regions W6 to W8 within the canopy 7D, which are made of a common material, can be adjusted by using different physical properties.

[0193] Additives to improve sliding properties can also be added to the cover tubes 7A to 7D.

[0194] <Other>

[0195] Base ends 212 and 222 are examples of the "first base end" of the present invention. Front end 221 is an example of the "first front end" of the present invention. Front end 30D is an example of the "second front end" of the present invention. Front end 3D is an example of the "third front end" of the present invention. Protrusions 4A, 4C-4E are examples of the "first protrusion" of the present invention. Protrusions 4B and 4I are examples of the "second protrusion" of the present invention. Vertex 410 is an example of the "first vertex" of the present invention. Front ramp 411 is an example of the "first front ramp" of the present invention. Base end ramp 412 is an example of the "first base end ramp" of the present invention. Protrusion 4G is an example of the "third protrusion" of the present invention. Protrusion 4H is an example of the "inner protrusion" of the present invention. Vertex 420 is an example of the "second vertex" of the present invention. Front ramp 421 is an example of the "second front ramp" of the present invention. The base slope portion 422 is an example of the "second base slope portion" of the present invention.

Claims

1. A balloon catheter, characterized in that, The balloon catheter has the following features: The conduit shaft extends along the extension direction over the entire range between the first base end and the first anterior end; A balloon, connected to the catheter shaft at a position where the distance between it and the first anterior end is shorter than the distance between it and the first basal end, and having an expansion portion and a front end connection portion, the expansion portion having a cylindrical shape extending along the extension direction, the front end connection portion being a portion extending from a second anterior end, which is the end closest to the first front end, toward the side opposite to the expansion portion, and the diameter of the end of the front end connection portion connected to the expansion portion is larger than the diameter of a third front end portion, which is the end opposite to the end connected to the expansion portion, and the front end connection portion is connected to the catheter shaft at the third anterior end portion; as well as A protrusion that projects radially outward relative to the central axis of the catheter shaft, and includes at least a first protrusion disposed on the portion of the balloon comprising the front end connection and the third anterior end portion. The front end connector has a region between the end of the protrusion closest to the second front end and the second front end portion that has a smaller protrusion than the protrusion of the protrusion.

2. The balloon catheter according to claim 1, characterized in that, The first protrusion has: The first vertex, which protrudes most outward in the radial direction; The first front ramp extends from the end near the third front portion toward the first vertex; as well as The first base slope portion extends from the end near the second front end portion toward the first vertex. The angle between the first base slope portion and the front end connecting portion is larger than the angle between the first front end slope portion and the front end connecting portion.

3. The balloon catheter according to claim 1 or 2, characterized in that, The protrusion also includes a third protrusion disposed on the inflatable portion of the balloon. The balloon catheter has an inner protrusion that extends over the entire range between the first and third protrusions and protrudes radially inward from the inner surface of the front end connector.

4. The balloon catheter according to claim 1 or 2, characterized in that, The first protrusion has a ring shape extending circumferentially around the central axis.

5. The balloon catheter according to claim 1 or 2, characterized in that, The first protrusion has a spiral shape extending circumferentially around the central axis.

6. The balloon catheter according to claim 1 or 2, characterized in that, The front end connector has multiple inclined portions. The plurality of inclined portions includes at least two inclined portions, and the at least two inclined portions form different inclination angles with the central axis along their respective directions extending from the second front end side toward the third front end side. The first protrusion is disposed in the inclined portion with the smallest inclination angle among the plurality of inclined portions.

7. The balloon catheter according to claim 1 or 2, characterized in that, The protrusion includes a second protrusion disposed in the front extension portion, which is a portion disposed in the extension direction between the third front end portion and the first front end portion of the balloon.

8. The balloon catheter according to claim 7, characterized in that, The second protrusion has multiple protrusions. The protrusion of each of the plurality of protrusions increases as it gets closer to the third anterior end.

9. The balloon catheter according to claim 7, characterized in that, The second protrusion has: The second vertex protrudes most outward in the radial direction; The second front ramp extends from the end near the first front portion toward the second vertex; as well as The second base slope portion extends from the end near the third front end portion toward the second vertex. The angle between the second base slope portion and the front extension portion is larger than the angle between the second front slope portion and the front extension portion.

10. The balloon catheter according to claim 1 or 2, characterized in that, The front extension portion has a region between the end of the protrusion closest to the first front end portion and the first front end portion, where the amount of protrusion is smaller than the amount of protrusion of the protrusion.

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