Balloon catheter and method for expanding balloon in balloon catheter

Abstract

To provide a balloon catheter having a high-pressure resistant balloon of a large diameter.SOLUTION: A balloon catheter includes: a shaft extending in a longitudinal direction from a proximal side to a distal side; and a balloon group composed of a first balloon disposed in a distal part of the shaft and a plurality of second balloons disposed aligned in a circumferential direction of the periphery of the first balloon. In a state that the first balloon and the balloon group are expanded, the adjacent second balloons constituting the balloon group come in contact with each other.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a balloon catheter and a method for expanding a balloon in the balloon catheter. [Background technology]

[0002] Diseases such as angina pectoris and myocardial infarction are caused by the formation of hardened stenotic areas on the inner walls of blood vessels due to calcification, etc. One of the treatment methods is angioplasty, which uses a balloon catheter to expand the stenotic area. Angioplasty is sometimes called percutaneous transluminal angioplasty (PTA) or percutaneous transluminal coronary angioplasty (PTCA). Angioplasty is a minimally invasive therapy that does not require open chest surgery like bypass surgery, and is widely performed.

[0003] A balloon catheter used in angioplasty has at least a shaft extending longitudinally from the proximal side to the distal side, a balloon disposed at the distal part of the shaft, and an inflation lumen communicating with the balloon and through which a fluid for expanding or contracting the balloon can move. The balloon is inserted into a blood vessel in a contracted state and delivered to the stenotic part through the blood vessel. After the balloon is delivered to the stenotic part, the expansion and contraction of the balloon are controlled by introducing or discharging a fluid into or from the inflation lumen using an indeflator (balloon pressurizer) connected to the inflation lumen.

[0004] An example of such a balloon catheter is described in Patent Document 1. Fig. 42 of Patent Document 1 describes an expansion device having an inner balloon member and multiple outer balloon members, and Fig. 43A shows the outer balloon members in an expanded state. In Patent Document 1, blood perfusion is achieved by forming a large space between adjacent outer balloon members. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US Patent Application Publication No. 2012 / 0209375 Summary of the Invention [Problem to be solved by the invention]

[0006] In the balloon catheter described in Patent Document 1, adjacent outer balloon members are separated from each other, so when the outer balloon member is pressed against the narrowed portion during dilation of the narrowed portion, it shifts in the circumferential direction of the inner balloon member, which is thought to prevent the narrowed portion from being sufficiently dilated. In addition, in order to dilate the narrowed portion, a balloon with a large diameter and high pressure resistance is required.

[0007] By the way, vascular stenosis also occurs in, for example, the aortic valve. When stenosis occurs in the aortic valve, the aortic valve is removed and a new biological valve is implanted. However, the placed biological valve deteriorates with time and needs to be replaced in about 5 to 10 years. When a treatment is performed to place a new biological valve (artificial valve) via a catheter due to deterioration of a surgically implanted biological valve (artificial valve), the valve orifice area may become narrow. Therefore, the size of the new biological valve needs to be smaller than the deteriorated biological valve, which reduces the blood flow rate and generates a pressure difference before and after the biological valve, which puts a strain on the heart. Therefore, it is thought that if the deteriorated biological valve that is placed is deformed or destroyed, a larger biological valve can be implanted. In order to deform or destroy the deteriorated biological valve, it is necessary to develop a balloon with a large diameter and high pressure resistance.

[0008] An object of the present invention is to provide a balloon catheter having a large diameter balloon with high pressure resistance. Another object of the present invention is to provide a method for expanding a balloon in a balloon catheter. [Means for solving the problem]

[0009] The present invention is as follows. [1] A balloon catheter comprising: a shaft extending longitudinally from the proximal side to the distal side; a first balloon disposed at the distal portion of the shaft; and a balloon group consisting of a plurality of second balloons disposed in a circumferential direction around the outer periphery of the first balloon, wherein, when the first balloon and the balloon group are inflated, adjacent second balloons that constitute the balloon group are in contact with each other. [2] The balloon catheter according to [1], wherein when the first balloon and the balloon group are inflated, the balloon group is in contact with the outer peripheral surface of the first balloon. [3] The balloon catheter according to [1] or [2], wherein when the first balloon and the balloon group are inflated, the second balloons that make up the balloon group all have the same maximum outer diameter, and the maximum outer diameter of the second balloons is the same as the maximum outer diameter of the first balloon. [4] The balloon catheter according to [1] or [2], wherein when the balloon group is inflated, the second balloons constituting the balloon group have two or more different maximum outer diameters. [5] The balloon catheter described in [4], wherein when the first balloon and the group of balloons are expanded, two types of second balloons having different maximum outer diameters are arranged circumferentially around the outer periphery of the first balloon, and the second balloon having the smaller maximum outer diameter is sandwiched between the second balloons having the larger maximum outer diameter. [6] The balloon catheter according to [1] or [2], wherein when the first balloon and the balloon group are inflated, the second balloons that make up the balloon group all have the same maximum outer diameter, and the maximum outer diameter of the second balloons is different from the maximum outer diameter of the first balloon. [7] A balloon catheter as described in [6], wherein the maximum outer diameter of the second balloon that constitutes the balloon group is smaller than the maximum outer diameter of the first balloon. [8] The balloon catheter described in [7], wherein the shaft has a first inflation lumen and a plurality of second inflation lumens extending in the longitudinal direction of the shaft, the first inflation lumen is connected to the first balloon, the plurality of second inflation lumens are connected to each of a plurality of second balloons that make up the balloon group, the plurality of second inflation lumens are connected to a single proximal second inflation lumen proximal to a connection position with the plurality of second balloons, and a cross-sectional area S2 of the proximal second inflation lumen in a direction perpendicular to the longitudinal direction is greater than a cross-sectional area S1 of the first inflation lumen in a direction perpendicular to the longitudinal direction. [9] A balloon catheter as described in [8], wherein the sum of the cross-sectional areas of the multiple second inflation lumens in a direction perpendicular to the longitudinal direction is greater than the cross-sectional area S1 of the first inflation lumen in a direction perpendicular to the longitudinal direction.

[10] A balloon catheter as described in [8] or [9], wherein the smallest cross-sectional area among the multiple second inflation lumens in a direction perpendicular to the longitudinal direction is greater than the cross-sectional area S1 of the first inflation lumen in a direction perpendicular to the longitudinal direction.

[11] A balloon catheter described in any of [1] to [6], wherein the shaft has a first inflation lumen and multiple second inflation lumens extending longitudinally of the shaft, the first inflation lumen is connected to the first balloon, and the multiple second inflation lumens are connected to each of the multiple second balloons that make up the balloon group.

[12] A balloon catheter as described in

[11] , wherein the multiple second inflation lumens are connected to one proximal second inflation lumen proximal to the connection position with the multiple second balloons.

[13] A balloon catheter as described in

[12] , wherein a cross-sectional area S1 in a direction perpendicular to the longitudinal direction of the first inflation lumen is the same as or greater than a cross-sectional area S2 in a direction perpendicular to the longitudinal direction of the proximal second inflation lumen.

[14] A balloon catheter as described in

[13] , wherein a cross-sectional area S1 of the first inflation lumen in a direction perpendicular to the longitudinal direction is the same as or greater than the sum of the cross-sectional areas of the second inflation lumens in a direction perpendicular to the longitudinal direction.

[15] A balloon catheter as described in

[13] or

[14] , wherein a cross-sectional area S1 of the first inflation lumen in a direction perpendicular to the longitudinal direction is the same as or greater than the largest cross-sectional area of ​​the multiple second inflation lumens in a direction perpendicular to the longitudinal direction.

[16] The balloon catheter described in any one of [1] to

[15] , which is used for expanding an aortic valve, deforming a biological valve placed in the heart, or destroying the biological valve.

[17] A method for expanding a balloon in a balloon catheter described in any one of [3] to [6], wherein a pressurizer expands the first balloon and then expands the group of balloons.

[18] A method for expanding a balloon in a balloon catheter described in [7], wherein a pressurizer expands the balloon group and then expands the first balloon. Effect of the Invention

[0010] The balloon catheter of the present invention has a first balloon and a balloon group composed of a plurality of second balloons arranged in a circumferential direction of the outer periphery of the first balloon, so that the outer diameter of the balloon of the balloon catheter including the first balloon and the balloon group can be increased by expanding both the first balloon and the balloon group. In addition, in the balloon catheter of the present invention, when the first balloon and the balloon group are expanded, the adjacent second balloons constituting the balloon group are in contact with each other, so that even if the second balloon is pressed against the narrowed portion, the first balloon is unlikely to shift in the circumferential direction of the outer periphery. As a result, the balloon group can reliably expand the narrowed portion. In addition, in the balloon catheter of the present invention, when the first balloon and the balloon group are expanded, the adjacent second balloons constituting the balloon group are in contact with each other, so that even if the pressure when expanding the second balloon is increased, the second balloons each suppress each other's expansion, and thus the second balloon has a high pressure resistance, and the hardness (expansion force) is increased. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a side view (partially see-through) of a balloon catheter according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a side view (partially see-through) of a balloon of a balloon catheter according to an embodiment of the present invention. [Diagram 3] FIG. 3 is a cross-sectional view of the balloon shown in FIG. 2 taken along line II. [Figure 4] FIG. 4 is a cross-sectional view of a balloon different from the balloon shown in FIG. [Diagram 5] FIG. 5 is a cross-sectional view of a balloon different from the balloon shown in FIG. [Figure 6] FIG. 6 is a longitudinal cross-sectional view of a shaft of a balloon catheter according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The balloon catheter of the present invention comprises a shaft extending longitudinally from the proximal side to the distal side, a first balloon disposed in the distal portion of the shaft, and a balloon group composed of a plurality of second balloons arranged in a circumferential direction around the outer periphery of the first balloon, and has a feature in that, when the first balloon and the balloon group are inflated, adjacent second balloons that make up the balloon group are in contact with each other.

[0013] The balloon catheter according to the embodiment of the present invention will be specifically described below with reference to the drawings, but the present invention is not limited to the illustrated examples, and can be modified within the scope of the above and below-mentioned purpose, and all of them are included in the technical scope of the present invention. In each drawing, hatching, symbols, etc. may be omitted for convenience, but in such cases, the specification and other drawings should be referred to. In addition, the dimensions of various parts in the drawings may differ from the actual dimensions because priority is given to contributing to understanding the features of the present invention.

[0014] Fig. 1 is a side view (partially see-through) of a balloon catheter according to an embodiment of the present invention. Fig. 2 is a side view (partially see-through) of a balloon of a balloon catheter according to an embodiment of the present invention. Fig. 2 shows a state in which a balloon group B consisting of a first balloon A and a plurality of second balloons is inflated. Fig. 3 is a cross-sectional view of the balloon shown in Fig. 2 taken along line II.

[0015] 1 and 2, a balloon catheter 1 according to an embodiment of the present invention has a shaft 10 extending longitudinally from the proximal side to the distal side, a first balloon A disposed at the distal portion of the shaft 10, and a balloon group B composed of a plurality of second balloons arranged in a line in the circumferential direction around the outer periphery of the first balloon A. In this specification, the balloon of the balloon catheter 1 including the first balloon A and the plurality of second balloons constituting the balloon group B may be referred to simply as a "balloon 2."

[0016] The shaft 10 has a longitudinal direction x, a radial direction y connecting the centroid of the outer edge of the shaft 10 and a point on the outer edge in a cross section perpendicular to the longitudinal direction x, and a circumferential direction z along the outer edge of the shaft 10 in a cross section perpendicular to the longitudinal direction x. In this specification, the direction toward the user's hand in the longitudinal direction x is referred to as the proximal side, and the opposite side to the proximal side, i.e., the direction toward the subject of treatment, is referred to as the distal side. In Figures 1 and 2, the left side of the figure is the proximal side (operator side), and the right side is the distal side (affected area side).

[0017] Members and parts other than the shaft 10 also have longitudinal directions, radial directions, and circumferential directions, which may or may not be the same as the longitudinal direction x, radial direction y, and circumferential direction z of the shaft 10. However, for ease of understanding, this specification will be described as assuming that all members and parts have the same longitudinal directions, radial directions, and circumferential directions as the longitudinal direction x, radial direction y, and circumferential direction z of the shaft 10.

[0018] The first balloon A and the second balloon are connected to the distal portion of the shaft 10. The first balloon A and the second balloon can be expanded by introducing a fluid through the inner cavity of the shaft 10, and the first balloon A and the second balloon can be deflated by discharging the fluid. In order to control the expansion and contraction of the first balloon A and the second balloon, a fluid can be introduced or discharged using an indeflator (a balloon pressurizer). For example, a mixture of a contrast agent and saline is used as the fluid. The fluid may be a pressurized fluid pressurized by a pump or the like.

[0019] The balloon catheter 1 shown in Figures 2 and 3 is composed of one first balloon A and six second balloons, and the six second balloons constitute a balloon group B. For ease of explanation, in Figures 2 and 3, two of the six second balloons are labeled with the symbols b1 and b2. When the first balloon A and the second balloons b1 and b2 are inflated, the maximum outer diameter of the first balloon A is Da, and the maximum outer diameters of the second balloons b1 and b2 are Db1 and Db2, respectively.

[0020] 2 and 3, the balloon catheter 1 according to the embodiment of the present invention has a balloon group B made up of a plurality of second balloons arranged in the circumferential direction z around the outer periphery of a first balloon A, and can increase the outer diameter of the balloon 2 by inflating both the first balloon A and the balloon group B. As a result, the stenotic area can be reliably dilated.

[0021] In the balloon catheter 1 according to the embodiment of the present invention, as shown in Figures 2 and 3, when the first balloon A and the balloon group B are inflated, the adjacent second balloons b1 and b2 of the multiple second balloons constituting the balloon group B are in contact with each other. By the adjacent second balloons b1 and b2 being in contact with each other, the second balloons suppress each other's expansion, thereby increasing the pressure resistance, and the expansion force of the balloon group B can be increased. In addition, by the adjacent second balloons b1 and b2 being in contact with each other, even if the second balloons come into contact with the stenosed portion, they are less likely to shift in the circumferential direction z of the outer periphery of the first balloon A, and the stenosed portion can be reliably expanded.

[0022] During inflation of the first balloon A and the balloon group B, at least one pair of adjacent second balloons in the multiple second balloons constituting the balloon group B need only be in contact with each other, preferably two or more pairs of adjacent second balloons are in contact with each other, and more preferably all adjacent second balloons are in contact with each other. Having all adjacent second balloons in contact with each other allows the second balloons to be inflated uniformly.

[0023] During the expansion of the first balloon A and the balloon group B, the second balloon constituting the balloon group B may not be in contact with the outer circumferential surface of the first balloon A, but it is preferable that at least one of the multiple second balloons constituting the balloon group B is in contact with the outer circumferential surface of the first balloon A. Since at least one of the multiple second balloons is in contact with the outer circumferential surface of the first balloon A, even if the second balloon is pressed against the narrowed portion, the second balloon is in contact with the outer circumferential surface of the first balloon A, so that the second balloon is less likely to shift in the radial direction y of the first balloon A, and the narrowed portion can be expanded reliably. It is more preferable that all of the multiple second balloons constituting the balloon group B are in contact with the outer circumferential surface of the first balloon A. Since all of the multiple second balloons are in contact with the outer circumferential surface of the first balloon A, even if the second balloon is pressed against the narrowed portion, the first balloon A and the second balloon expand each other, so that the balloon group B can be made to have a high pressure resistance.

[0024] The number of the second balloons constituting the balloon group B is preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more. By setting the lower limit of the number of the second balloons constituting the balloon group B within the above range, the balloon group B can easily surround the outer periphery of the first balloon A, and the balloon group B can easily suppress the expansion of the first balloon A. As a result, when a fluid is introduced into both the first balloon A and the balloon group B, the first balloon A and the balloon group B mutually suppress the expansion of each other, so that the balloon 2 is made to withstand high pressure, and the hardness of the balloon 2 is increased, thereby improving the expansion force. In addition, the first balloon A and the balloon group B mutually suppress the expansion of each other, so that the balloon 2 is difficult to expand, and therefore even if a high pressure is applied to the balloon 2, overexpansion of the balloon 2 is suppressed, and the balloon 2 is prevented from expanding beyond the targeted outer diameter, and damage to the biological lumen such as the aortic valve is reduced, thereby improving safety. The upper limit of the number of second balloons constituting balloon group B is not particularly limited, but is, for example, preferably 20 or less, more preferably 12 or less, even more preferably 10 or less, and particularly preferably 8 or less. By setting the upper limit of the number of second balloons constituting balloon group B within the above range, the second balloons constituting balloon group B are less likely to shift in the radial direction y and circumferential direction z of the first balloon A, making it easier for balloon group B to suppress the expansion of the first balloon A.

[0025] When the first balloon A and the balloon group B are inflated, the maximum outer diameter of the circumscribing circle of the balloon 2 is not particularly limited, but is preferably in the range of, for example, 5 mm to 60 mm.

[0026] The relationship between the maximum outer diameter of the first balloon A and the maximum outer diameter of the second balloon constituting the balloon group B preferably satisfies, for example, any one of the following (1) to (3). (1) When the first balloon A and the balloon group B are inflated, the second balloons that make up the balloon group B all have the same maximum outer diameter, and the maximum outer diameter of the second balloons is the same as the maximum outer diameter of the first balloon A. (2) When balloon group B is inflated, the second balloons constituting balloon group B have two or more different maximum outer diameters. (3) When the first balloon A and the balloon group B are inflated, the second balloons that make up the balloon group B all have the same maximum outer diameter, and the maximum outer diameter of the second balloons is different from the maximum outer diameter of the first balloon A.

[0027] The maximum outer diameter of the first balloon A refers to the maximum equivalent circle diameter of the first balloon A in a cross section perpendicular to the longitudinal direction x of the first balloon A. The maximum outer diameter of the second balloon refers to the maximum equivalent circle diameter of the second balloon in a cross section perpendicular to the longitudinal direction x of the second balloon.

[0028] (1) will be explained with reference to Fig. 3. As shown in Fig. 3, when the first balloon A and the balloon group B are expanded, the second balloons constituting the balloon group B all have the same maximum outer diameter, and the maximum outer diameter of the second balloon is the same as the maximum outer diameter of the first balloon A. This makes it easier to balance the force exerted by the first balloon A to expand and the force exerted by the second balloon to suppress the expansion of the first balloon A. As a result, the hardness of the first balloon A and the balloon group B is increased, making it easier to increase the expansion force of the balloon group B, and enabling the stenosis to be expanded uniformly.

[0029] When the first balloon A and all the second balloons have the same maximum outer diameter, the maximum outer diameters of the first balloon A and the second balloon are preferably, for example, 3 mm to 8 mm. The fact that the second balloons constituting balloon group B all have the same maximum outer diameter means that the maximum outer diameters of the second balloons constituting balloon group B are approximately the same, specifically, that the maximum outer diameter of the second balloon constituting balloon group B with the smallest maximum outer diameter is 100% or more and 110% or less. The fact that the maximum outer diameter of the first balloon A is the same as the maximum outer diameter of the second balloons constituting balloon group B means that the maximum outer diameter of the first balloon A and the maximum outer diameter of the second balloons constituting balloon group B are approximately the same, specifically, that the maximum outer diameter of the first balloon A is 90% or more and 110% or less of the maximum outer diameter (e.g., average value) of the second balloons.

[0030] (2) will be described with reference to FIG. 4. FIG. 4 is a cross-sectional view of a balloon different from the balloon shown in FIG. 2, at a position corresponding to FIG. 3. As shown in FIG. 4, when the balloon group B is inflated, the second balloons constituting the balloon group B are of two or more different sizes of maximum outer diameter, and therefore a plurality of second balloons with different maximum outer diameters are arranged in the circumferential direction z of the outer periphery of the first balloon A. Therefore, the second balloons b11 and b12 with the larger maximum outer diameter among the balloon group B contact the inner wall of the blood vessel, and the second balloons b13 and b14 with the smaller maximum outer diameter do not contact the inner wall of the blood vessel. Therefore, a space is easily formed between the inner wall of the blood vessel and the second balloons b13 and b14 that do not contact the inner wall of the blood vessel, and blood can be perfused. In addition, the second balloons b11 and b12 with the larger maximum outer diameter among the balloon group B contact the inner wall of the blood vessel, and therefore the number of the second balloons in the balloon group B that contact the inner wall of the blood vessel is limited to a certain number, so that the number of contact points between the second balloons and the inner wall of the blood vessel is reduced, and the stress applied from the second balloons to the inner wall of the blood vessel can be concentrated. As a result, the narrowed area can be reliably expanded.

[0031] When the number of second balloons constituting the balloon group B is at least three, and when the first balloon A and the balloon group B are inflated, two types of second balloons with different maximum outer diameters are arranged in the circumferential direction z around the outer periphery of the first balloon A, it is preferable that the second balloon b13 with the smaller maximum outer diameter is sandwiched between the second balloons b11, b12 with the larger maximum outer diameter, as shown in Fig. 4. By sandwiching the second balloon with the smaller maximum outer diameter between the second balloons with the larger maximum outer diameter in the circumferential direction z around the outer periphery of the first balloon A, the spaces formed between the inner wall of the blood vessel and the second balloons not in contact with the inner wall of the blood vessel are distributed in the circumferential direction z around the outer periphery of the first balloon A, thereby enabling stable blood perfusion.

[0032] During inflation of balloon group B, the second balloons constituting balloon group B may have, for example, two, three, or four or more different maximum outer diameters. Of these, it is preferable that the second balloons constituting balloon group B have two different maximum outer diameters.

[0033] As shown in FIG. 4, when the first balloon A and the balloon group B are inflated, if the multiple second balloons constituting the balloon group B are of two different types with different maximum outer diameters, the ratio (Db11 / Db13) of the maximum outer diameter Db11 of the second balloon b11 having the larger maximum outer diameter to the maximum outer diameter Db13 of the second balloon b13 having the smaller maximum outer diameter is, for example, preferably greater than 1 and less than 5, more preferably 1.1 or more, even more preferably greater than 1.1, particularly preferably 2 or more, most preferably 2.5 or more, more preferably 4.5 or less, and even more preferably 4 or less.

[0034] As shown in FIG. 4, when the first balloon A and the balloon group B are inflated, if the second balloons constituting the balloon group B have two different maximum outer diameters, the maximum outer diameter Db13 of the second balloon b13 having the smaller maximum outer diameter is preferably, for example, 3 mm to 5 mm, and the maximum outer diameter Db11 of the second balloon b11 having the larger maximum outer diameter is preferably, for example, 3.1 mm to 25 mm (particularly, more than 3.3 mm and not more than 25 mm).

[0035] (3) will be described with reference to FIG. 5. FIG. 5 is a cross-sectional view of a balloon different from the balloon shown in FIG. 2, taken at a position corresponding to FIG. 3. As shown in FIG. 5, when the first balloon A and the balloon group B are inflated, the maximum outer diameters of the second balloons constituting the balloon group B are all the same. However, since the maximum outer diameter of the second balloon is different from the maximum outer diameter of the first balloon A, the first balloon A and the second balloon having different maximum outer diameters can be appropriately combined to adjust the maximum outer diameter of the balloon group B, making it easier to adjust the maximum outer diameter of the balloon group B. The fact that the maximum outer diameters of the second balloons constituting the balloon group B are all the same means that the maximum outer diameters of the second balloons constituting the balloon group B are approximately the same. Specifically, this means that the maximum outer diameter of the second balloon with the largest maximum outer diameter among the second balloons constituting the balloon group B is 100% or more and 110% or less of the maximum outer diameter of the second balloon with the smallest maximum outer diameter among the second balloons constituting the balloon group B.

[0036] In the case of (3), when the first balloon A and balloon group B are inflated, the maximum outer diameter of the second balloons constituting balloon group B may be larger or smaller than the maximum outer diameter of the first balloon A, but is preferably smaller. By having the maximum outer diameter of the second balloons constituting balloon group B smaller than the maximum outer diameter of the first balloon A, the first balloon A can be inflated with high pressure, and the narrowed area can be reliably inflated.

[0037] When the maximum outer diameter of the multiple second balloons that make up balloon group B is greater than the maximum outer diameter of the first balloon A, the ratio of the maximum outer diameter Db21 of the second balloon b21 to the maximum outer diameter Da of the first balloon A (Db21 / Da) is, for example, preferably greater than 1 and less than 4.5, more preferably greater than 1.1, even more preferably greater than 1.1, particularly preferably greater than 1.2, and more preferably less than 4, even more preferably less than 3.

[0038] When the maximum outer diameter of the multiple second balloons that make up balloon group B is greater than the maximum outer diameter of the first balloon A, the maximum outer diameter Da of the first balloon A is preferably, for example, 3 mm to 5 mm, and the maximum outer diameter Db21 of the second balloon b21 is preferably, for example, 3.1 mm to 13.5 mm (particularly, greater than 3.3 mm and equal to or less than 13.5 mm).

[0039] When the maximum outer diameter of the multiple second balloons that make up balloon group B is smaller than the maximum outer diameter of the first balloon A, the ratio of the maximum outer diameter Db21 of the second balloon b21 to the maximum outer diameter Da of the first balloon A (Db21 / Da) is, for example, preferably 0.01 or more and less than 1, more preferably 0.03 or more, even more preferably 0.05 or more, more preferably less than 0.9, even more preferably 0.2 or less, and particularly preferably 0.1 or less.

[0040] When the maximum outer diameter of the multiple second balloons that make up balloon group B is smaller than the maximum outer diameter of the first balloon A, the maximum outer diameter Da of the first balloon A is preferably, for example, 3 mm to 20 mm, and the maximum outer diameter Db21 of the second balloon b21 is preferably, for example, 1.0 mm to 5 mm.

[0041] In the case of (3), it is preferable that the shaft 10 has at least a first inflation lumen and a plurality of second inflation lumens extending in the longitudinal direction x of the shaft 10, and it is preferable that the first inflation lumen is connected to the first balloon A and the plurality of second inflation lumens are connected to each of the plurality of second balloons that constitute the balloon group B.

[0042] Since the shaft 10 has a first inflation lumen connected to the first balloon A and a plurality of second inflation lumens connected to each of the plurality of second balloons, a balloon pressurizer connected to the first inflation lumen and a balloon pressurizer connected to each of the plurality of second inflation lumens can be used to introduce fluid into each lumen or discharge fluid from each lumen. This allows the timing of inflation or deflation of the first balloon A and the plurality of second balloons to be controlled, respectively. Also, the inflation pressure of the first balloon A and the plurality of second balloons can be controlled, respectively. As a result, it is possible to respond to various treatments and situations.

[0043] It is preferable that the second inflation lumens communicate with one proximal second inflation lumen proximal to the connection position with the second balloons. Such a configuration will be described with reference to FIG. 6. FIG. 6 is a cross-sectional view of the shaft 10 in the longitudinal direction x of the balloon catheter 1 according to an embodiment of the present invention, and in FIG. 6, the left side of the figure is the proximal side (operator side), and the right side is the distal side (affected area side). As shown in FIG. 6, the shaft 10 has a first inflation lumen La, a second inflation lumen Lb1, and a second inflation lumen Lb2. In FIG. 6, a guidewire tube 40 is disposed in the first inflation lumen La, and the guidewire tube 40 has a guidewire lumen L40. When the first balloon A (not shown) is connected to the first inflation lumen La, the second balloon b1 (not shown) is connected to the second inflation lumen Lb1, and the second balloon b2 (not shown) is connected to the second inflation lumen Lb2, it is preferable that the second inflation lumen Lb1 and the second inflation lumen Lb2 communicate with one proximal second inflation lumen Lb proximal to the connection position with the second balloons b1, b2. Since the proximal second inflation lumen Lb communicates with a plurality of second inflation lumens Lb1, Lb2, the fluid introduced using the balloon pressurizer connected to the proximal second inflation lumen Lb is introduced from the proximal second inflation lumen Lb through the second inflation lumen Lb1 and the second inflation lumen Lb2 to the second balloons b1, b2, so that the second balloons b1, b2 can be inflated simultaneously. In addition, when discharging fluid from the second balloons b1, b2, the fluid can be discharged through the second inflation lumens Lb1, Lb2 using a balloon compressor connected to the proximal second inflation lumen Lb, thereby allowing the second balloons b1, b2 to be deflated simultaneously.

[0044] When the second inflation lumens communicate with one proximal second inflation lumen Lb proximal to the connection position with the second balloons, the cross-sectional area S2 of the proximal second inflation lumen Lb in a direction perpendicular to the longitudinal direction x is preferably larger than the cross-sectional area S1 of the first inflation lumen La in a direction perpendicular to the longitudinal direction x. Since the cross-sectional area S2 is larger than the cross-sectional area S1, the balloon group B expands before the first balloon A, and therefore the balloon group B can be expanded uniformly.

[0045] When the cross-sectional area S2 is larger than the cross-sectional area S1, it is preferable that the sum of the cross-sectional areas of the second inflation lumens in a direction perpendicular to the longitudinal direction x is larger than the cross-sectional area S1 and / or the smallest cross-sectional area of ​​the second inflation lumens in a direction perpendicular to the longitudinal direction x is larger than the cross-sectional area S1. When the sum of the cross-sectional areas of the second inflation lumens in a direction perpendicular to the longitudinal direction x is larger than the cross-sectional area S1, the balloon group B expands before the first balloon A, so that the balloon group B can be expanded uniformly. When the smallest cross-sectional area of ​​the cross-sectional areas of the second inflation lumens in a direction perpendicular to the longitudinal direction x is larger than the cross-sectional area S1, the balloon group B expands before the first balloon A, so that the balloon group B can be expanded uniformly.

[0046] In the balloon catheter 1 according to the embodiment of the present invention, the shaft 10 has a first inflation lumen La and a plurality of second inflation lumens extending in the longitudinal direction x of the shaft 10, and it is preferable that the first balloon A is connected to the first inflation lumen La, and the second balloons constituting the balloon group B are connected to each of the plurality of second inflation lumens. By connecting a pressurizer that introduces or discharges a fluid for expanding or contracting the first balloon A to the first inflation lumen La to which the first balloon A is connected, and connecting a pressurizer that introduces or discharges a fluid for expanding or contracting the second balloon to the second inflation lumen to which the second balloon constituting the balloon group B is connected, the fluid for expanding or contracting the first balloon A and the second balloon can be introduced or discharged at different times to the first inflation lumen La and the plurality of second inflation lumens, respectively. As a result, the first balloon A and the plurality of second balloons can be expanded or contracted at different times. For example, by introducing a fluid using a balloon pressurizer connected to the first inflation lumen La, and then introducing a fluid into each lumen using a balloon pressurizer connected to each of the second inflation lumens, the first balloon A can be inflated first, followed by the second balloons. Also, by connecting a pressurizer to the first inflation lumen La and each of the second inflation lumens, the inflation pressures of the first balloon A and the second balloons can be controlled respectively. As a result, it is possible to respond to various treatments and situations.

[0047] When the second balloons constituting balloon group B are connected to each of the second inflation lumens, it is preferable that the second inflation lumens communicate with one proximal second inflation lumen proximal to the connection positions with the second balloons. When a pressurizer that introduces or discharges a fluid for expanding or contracting the second balloon is connected to the proximal second inflation lumen, and a fluid is introduced from the pressurizer, for example, the fluid passes through the proximal second inflation lumen and is introduced into each of the second inflation lumens at the same time, so that the second balloons can be expanded at the same time.

[0048] When the second inflation lumens are connected to one proximal second inflation lumen proximal to the connection position with the second balloon, the cross-sectional area S1 of the first inflation lumen La in a direction perpendicular to the longitudinal direction x is preferably equal to or greater than the cross-sectional area S2 of the proximal second inflation lumen in a direction perpendicular to the longitudinal direction x. By making the cross-sectional area S1 equal to the cross-sectional area S2, the second balloons and the first balloon A can be inflated simultaneously. By making the cross-sectional area S1 greater than the cross-sectional area S2, the first balloon A can be inflated prior to the second balloons.

[0049] When the cross-sectional area S1 is equal to or greater than the cross-sectional area S2, it is preferable that the cross-sectional area S1 is equal to or greater than the sum of the cross-sectional areas of the second inflation lumens in a direction perpendicular to the longitudinal direction x. By having the cross-sectional area S1 equal to the sum of the cross-sectional areas of the second inflation lumens in a direction perpendicular to the longitudinal direction x, the second balloons and the first balloon A can be inflated simultaneously. By having the cross-sectional area S1 greater than the sum of the cross-sectional areas of the second inflation lumens in a direction perpendicular to the longitudinal direction x, the first balloon A can be inflated prior to the second balloons.

[0050] When the cross-sectional area S1 is equal to or larger than the cross-sectional area S2, it is preferable that the cross-sectional area S1 is equal to or larger than the largest cross-sectional area among the multiple second inflation lumens in a direction perpendicular to the longitudinal direction x. Since the cross-sectional area S1 is equal to the largest cross-sectional area among the multiple second inflation lumens in a direction perpendicular to the longitudinal direction x, the multiple second balloons and the first balloon A can be inflated simultaneously. Since the cross-sectional area S1 is larger than the largest cross-sectional area among the multiple second inflation lumens in a direction perpendicular to the longitudinal direction x, the first balloon A can be inflated prior to the multiple second balloons.

[0051] The first balloon A and second balloon of the balloon catheter 1 according to an embodiment of the present invention preferably have a straight tube section 23, a proximal taper section 22 located proximal to the straight tube section 23, and a distal taper section 24 located distal to the straight tube section 23, and may also have a proximal sleeve section 21 located proximal to the proximal taper section 22 and a distal sleeve section 25 located distal to the distal taper section 24.

[0052] When the first balloon A and the balloon group B are expanded, the length L1 from the distal end Ad of the first balloon A to the proximal end Ap of the first balloon A in the longitudinal direction x may be the same as the length L2 from the distal end b1d of the second balloon b1 to the proximal end b1p of the second balloon b1 in the longitudinal direction x, but is preferably shorter. Since the length L1 of the first balloon A is shorter than the length L2 of the second balloon b1, the part where the first balloon A exists is more likely to expand than the part where the first balloon A does not exist. As a result, it is easier to apply pressure to the part where the first balloon A exists, and it is possible to accurately apply pressure to the target location. In addition, since it is difficult to expand greatly and it is difficult to apply pressure to the part where the first balloon A does not exist, it is difficult to apply load to the part that is not the target location, and the low invasiveness of the balloon catheter 1 can be improved.

[0053] When the first balloon A and the balloon group B are inflated, the length L1 from the distal end Ad of the first balloon A to the proximal end Ap of the first balloon A in the longitudinal direction x is preferably 95% or less, more preferably 90% or less, and even more preferably 85% or less of the length L2 from the distal end b1d of the second balloon b1 to the proximal end b1p of the second balloon b1 in the longitudinal direction x. By setting the upper limit of the ratio of the length L1 of the first balloon A to the length L2 of the second balloon b1 within the above range, the balloon catheter 1 can be made to easily apply high pressure accurately to the target location. Furthermore, during expansion of the first balloon A and the balloon group B, the length L1 from the distal end Ad of the first balloon A to the proximal end Ap of the first balloon A in the longitudinal direction x is preferably 20% or more, more preferably 25% or more, and even more preferably 30% or more of the length L2 from the distal end b1d of the second balloon b1 to the proximal end b1p of the second balloon b1 in the longitudinal direction x. By setting the lower limit of the ratio of the length L1 of the first balloon A to the length L2 of the second balloon b1 within the above range, it becomes easier to apply pressure to a sufficient area of ​​the target location using the balloon catheter 1, making it easier to expand a stenotic area or destroy a biological valve.

[0054] As shown in FIG. 1, a balloon catheter 1 according to an embodiment of the present invention can be, for example, a so-called rapid exchange type balloon catheter, which has a guidewire port 50 midway from the distal side to the proximal side of the shaft 10 and has a guidewire insertion passage from the guidewire port 50 to the distal side of the shaft 10.

[0055] As shown in FIG. 1, a balloon catheter 1 according to an embodiment of the present invention has a hub 5 on the proximal side, and the hub 5 is provided with a fluid injection section 6 for injecting a fluid to expand or contract the balloon 2.

[0056] The shaft 10 of the balloon catheter 1 according to the embodiment of the present invention may further include a guidewire tube 40 extending in the longitudinal direction x, as shown in Fig. 6. A portion of the guidewire tube 40 is preferably disposed in the lumen of the first balloon A, as shown in Fig. 1.

[0057] Examples of materials constituting the shaft 10 include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, fluorine resins, vinyl chloride resins, silicone resins, and natural rubber. These materials may be used alone or in combination of two or more. Among them, the material constituting the shaft 10 is preferably at least one selected from polyamide resins, polyolefin resins, and fluorine resins. By using any one of polyamide resins, polyolefin resins, and fluorine resins, the surface of the shaft 10 has high slipperiness, thereby improving the insertability of the balloon catheter 1 in a blood vessel.

[0058] 1, the shaft 10 of the balloon catheter 1 preferably has a distal shaft 15 and a proximal shaft 16 disposed proximally of the distal shaft 15, and the distal shaft 15 and the proximal shaft 16 may be separate members. When the distal shaft 15 and the proximal shaft 16 are separate members, the proximal shaft 16 may be made of resin or metal.

[0059] In the case of a rapid exchange type balloon catheter as shown in FIG. 1, it is preferable that a coating is applied to the outer wall of the proximal shaft 16 and / or the distal shaft 15, and it is more preferable that a coating is applied to both the proximal shaft 16 and the distal shaft 15.

[0060] The coating can be a hydrophilic coating or a hydrophobic coating depending on the purpose, and can be applied by immersing the shaft 10 in a hydrophilic or hydrophobic coating agent, applying a hydrophilic or hydrophobic coating agent to the outer wall of the shaft 10, or covering the outer wall of the shaft 10 with a hydrophilic or hydrophobic coating agent. The coating agent may contain drugs or additives.

[0061] Examples of hydrophilic coating agents include hydrophilic polymers such as polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, methyl vinyl ether maleic anhydride copolymer, and the like, or hydrophilic coating agents made of any combination thereof.

[0062] Examples of hydrophobic coating agents include polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxyalkane (PFA), silicone oil, hydrophobic urethane resin, carbon coat, diamond coat, diamond-like carbon (DLC) coat, ceramic coat, and substances terminated with alkyl groups or perfluoroalkyl groups and having low surface free energy.

[0063] Although not shown, the balloon catheter 1 according to the embodiment of the present invention can also be applied to a so-called over-the-wire type balloon catheter having a guidewire passage from the distal side to the proximal side of the shaft. In the case of an over-the-wire type balloon catheter, it is preferable that the inflation lumen and the guidewire lumen extend to the hub 5 located on the hand side, and the proximal opening of each lumen is provided in the hub 5 having a bifurcated structure. In the case of an over-the-wire type balloon catheter, it is preferable that the outer wall of the outer shaft is coated. For the material and coating constituting the shaft, the explanation for the rapid exchange type balloon catheter can be referred to.

[0064] Examples of materials constituting the first balloon A and the second balloon include polyolefin-based resins such as polyethylene, polypropylene, and ethylene-propylene copolymer; polyester-based resins such as polyethylene terephthalate and polyester elastomer; polyurethane-based resins such as polyurethane and polyurethane elastomer; polyphenylene sulfide-based resins; polyamide-based resins such as polyamide and polyamide elastomer; fluorine-based resins; silicone-based resins; and natural rubbers such as latex rubber. These may be used alone or in combination of two or more. Among them, the material constituting the first balloon A and the second balloon is preferably at least one selected from polyamide-based resins, polyester-based resins, and polyurethane-based resins.

[0065] The material constituting the first balloon A and the second balloon is preferably an elastomer resin in terms of thinning and flexibility. For example, among polyamide resins, nylon 12, nylon 11, etc. are suitable as materials constituting the first balloon A and the second balloon. Nylon 12 is more suitable because it can be molded relatively easily during blow molding. In addition, polyamide elastomers such as polyether ester amide elastomers and polyamide ether elastomers are preferably used in terms of thinning and flexibility of the first balloon A and the second balloon. Among them, polyether ester amide elastomers are preferably used in terms of high yield strength and good dimensional stability of the first balloon A and the second balloon.

[0066] The material constituting the first balloon A and the material constituting the second balloon may be the same, but it is preferable that they are different, and it is preferable to select a material such that the pressure resistance value P2 of the second balloon is greater than the pressure resistance value P1 of the first balloon A. The materials constituting the multiple second balloons may be different, but it is preferable that they are the same. By using the same materials, the degree of expansion, hardness, etc. of each second balloon can be made to be approximately the same.

[0067] The shaft 10 disposed inside the first balloon A may have a radiopaque marker 70 disposed in the portion where the first balloon A is located in the longitudinal direction x so that the position of the first balloon A can be confirmed under X-ray fluoroscopy. The radiopaque marker 70 is preferably disposed at positions corresponding to both ends of the straight tube portion 23 of the first balloon A, and may be disposed at a position corresponding to the center of the straight tube portion 23 of the first balloon A.

[0068] The shape of the radiopaque marker 70 is preferably tubular, and examples of such shapes include a cylindrical shape, a polygonal cylindrical shape, a C-shaped cross section with a notch in the tube, a coil shape with a wound wire, etc. The material constituting the radiopaque marker 70 may be, for example, a radiopaque substance such as lead, barium, iodine, tungsten, gold, platinum, iridium, stainless steel, titanium, or a cobalt chromium alloy.

[0069] The distal end of the balloon catheter 1 according to the embodiment of the present invention is preferably provided with a tip member 60. The tip member 60 may be provided at the distal end of the balloon catheter 1 as a separate member from the shaft 10 and connected to the distal end of the first balloon A, or the distal end of the shaft 10 may function as the tip member 60 by extending distally beyond the distal end of the first balloon A.

[0070] The balloon catheter 1 according to the embodiment of the present invention can be used, for example, to dilate a blood vessel, and can be particularly suitably used to dilate an aortic valve, deform a biological valve placed in the heart, or destroy the biological valve. By deforming or destroying a biological valve placed in the heart, a larger biological valve can be implanted, and the pressure difference across the biological valve can be improved.

[0071] Next, a method for expanding the balloon 2 of the balloon catheter 1 according to the embodiment of the present invention will be described.

[0072] A balloon catheter 1 according to an embodiment of the present invention has a shaft 10 extending from a proximal side to a distal side in a longitudinal direction x, a first balloon A disposed at the distal portion of the shaft 10, and a balloon group B composed of a plurality of second balloons arranged side by side in a circumferential direction z around the outer periphery of the first balloon A, and when the first balloon A and the balloon group B are inflated, adjacent second balloons constituting the balloon group B are in contact with each other, and (a) the second balloons constituting the balloon group B all have the same maximum outer diameter and the maximum outer diameter of the second balloon is the same as the maximum outer diameter of the first balloon A, (b) the second balloons constituting the balloon group are of two or more different maximum outer diameters, or (c) the second balloons constituting the balloon group all have the same maximum outer diameter and the maximum outer diameter of the second balloon is different from the maximum outer diameter of the first balloon A, it is preferable to inflate the first balloon A and then inflate the balloon group B using a pressurizer. By expanding the first balloon A before the second balloon, the second balloon expands along the outer peripheral surface of the first balloon, and therefore the second balloon expands without shifting in the radial direction y of the first balloon A.

[0073] A balloon catheter 1 according to an embodiment of the present invention includes a shaft 10 extending from the proximal side to the distal side in the longitudinal direction x, a first balloon A disposed at the distal portion of the shaft 10, and a balloon group B consisting of a plurality of second balloons arranged side by side in the circumferential direction z of the outer periphery of the first balloon A, and when the first balloon A and the balloon group B are inflated, the adjacent second balloons constituting the balloon group B are in contact with each other, the maximum outer diameters of the second balloons constituting the balloon group B are all the same, the maximum outer diameter of the second balloon is different from the maximum outer diameter of the first balloon A, and the maximum outer diameter of the second balloon constituting the balloon group B is smaller than the maximum outer diameter of the first balloon A, it is preferable to inflate the balloon group B and then inflate the first balloon A by a pressurizer. By inflating the second balloon before the first balloon A, the second balloon can be uniformly inflated. [Explanation of symbols]

[0074] 1 Balloon catheter 2. Balloon 5 Hub 6 Fluid injection part 10 Shaft 15 Distal Shaft 16 Proximal Shaft 21 Proximal sleeve part 22 Proximal taper 23 Straight pipe section 24 Distal tapered section 25 Distal sleeve 40 Guidewire tube 50 Guidewire Port 60 Tip Parts 70 Radiopaque Markers 90 Boundary between distal shaft 15 and proximal shaft 16 A First balloon B Balloon group b1, b2, b11~b14, b21~b23 Second balloon Da Maximum outer diameter of first balloon Db1, Db2, Db11~Db14, Db21~Db23 Maximum outer diameter of second balloon L40 Guidewire Lumen La First Inflation Lumen Lb Proximal Second Inflation Lumen Lb1, Lb2 Second inflation lumen

Claims

1. A shaft that extends longitudinally from the proximal side to the distal side, The first balloon is located at the distal end of the shaft, A balloon group consisting of a plurality of second balloons arranged in a circumferential direction around the outer circumference of the first balloon, It has, When the first balloon and the balloon group are expanded, adjacent second balloons constituting the balloon group are in contact with each other. The shaft has a first inflation lumen and a plurality of second inflation lumens extending in the longitudinal direction of the shaft. The first inflation lumen is connected to the first balloon, The plurality of second inflation lumens are connected to each of the plurality of second balloons that constitute the balloon group, A balloon catheter in which the plurality of second inflation lumens communicate with one proximal second inflation lumen at a location proximal to the connection point with the plurality of second balloons.

2. The balloon catheter according to claim 1, wherein, when the first balloon and the balloon group are expanded, the balloon group is in contact with the outer surface of the first balloon.

3. The balloon catheter according to claim 1, wherein, when the first balloon and the balloon group are expanded, the maximum outer diameters of all the second balloons constituting the balloon group are the same, and the maximum outer diameter of the second balloons is the same as the maximum outer diameter of the first balloon.

4. The balloon catheter according to claim 1, wherein, when the balloon group is expanded, there are two or more second balloons constituting the balloon group that have different maximum outer diameters.

5. The balloon catheter according to claim 4, wherein, when the first balloon and the balloon group are expanded, two types of second balloons with different maximum outer diameters are arranged circumferentially around the outer circumference of the first balloon, and the second balloon with the smaller maximum outer diameter is sandwiched between the second balloons with the larger maximum outer diameter.

6. The balloon catheter according to claim 1, wherein, when the first balloon and the balloon group are expanded, the maximum outer diameters of all second balloons constituting the balloon group are the same, and the maximum outer diameter of the second balloons is different from the maximum outer diameter of the first balloon.

7. The balloon catheter according to claim 6, wherein the maximum outer diameter of the second balloon constituting the balloon group is smaller than the maximum outer diameter of the first balloon.

8. The balloon catheter according to claim 7, wherein the cross-sectional area S2 of the proximal second inflation lumen in a direction perpendicular to the longitudinal direction is greater than the cross-sectional area S1 of the first inflation lumen in a direction perpendicular to the longitudinal direction.

9. The balloon catheter according to claim 8, wherein the sum of the cross-sectional areas of the plurality of second inflation lumens in a direction perpendicular to the longitudinal direction is greater than the cross-sectional area S1 of the first inflation lumen in a direction perpendicular to the longitudinal direction.

10. The balloon catheter according to claim 8, wherein the smallest cross-sectional area among the plurality of second inflation lumens in a direction perpendicular to the longitudinal direction is greater than the cross-sectional area S1 of the first inflation lumen in a direction perpendicular to the longitudinal direction.

11. The balloon catheter according to claim 1, wherein the cross-sectional area S1 of the first inflation lumen in a direction perpendicular to the longitudinal direction is the same as or greater than the cross-sectional area S2 of the proximal second inflation lumen in a direction perpendicular to the longitudinal direction.

12. The balloon catheter according to claim 11, wherein the cross-sectional area S1 of the first inflation lumen in a direction perpendicular to the longitudinal direction is equal to or greater than the sum of the cross-sectional areas of the plurality of second inflation lumens in a direction perpendicular to the longitudinal direction.

13. The balloon catheter according to claim 11, wherein the cross-sectional area S1 of the first inflation lumen in a direction perpendicular to the longitudinal direction is the same as or greater than the largest cross-sectional area among the plurality of second inflation lumens in a direction perpendicular to the longitudinal direction.

14. The balloon catheter according to claim 1, which is used to dilate the aortic valve, deform a bioprosthetic valve implanted in the heart, or destroy the bioprosthetic valve.

15. A method for expanding a balloon in a balloon catheter according to any one of claims 3 to 6, wherein the pressurizer expands the balloon group after expanding the first balloon.

16. A method for expanding a balloon in a balloon catheter according to claim 7, wherein the pressurizer expands the balloon group and then expands the first balloon.

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