Balloon catheter and method for expanding balloon of said balloon catheter

Abstract

Provided are a balloon catheter having a balloon with a large diameter and a high pressure resistance, a balloon catheter having a balloon that is easy to insert into a blood vessel, expands to a large diameter, and is also provided with a perfusion function when expanded, and a method for expanding a balloon of a balloon catheter.　This balloon catheter has: a shaft that extends in a longitudinal direction from a proximal side to a distal side; a first balloon that is provided to a distal section of the shaft; and a balloon group that is configured from a plurality of second balloons that are provided arranged side by side in the circumferential direction of the outer circumference of the first balloon. When the first balloon and the balloon group are expanded, neighboring second balloons constituting the balloon group are in contact with each other.

Description

Balloon catheter and method for expanding balloon in said balloon catheter

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

[0002] The formation of hardened stenotic areas due to calcification and other factors on the inner walls of blood vessels can lead to diseases such as angina pectoris and myocardial infarction. One of the treatment methods for these conditions is angioplasty, which uses a balloon catheter to dilate the stenotic area. Angioplasty is sometimes called percutaneous transluminal angioplasty (PTA) or percutaneous transluminal coronary angioplasty (PTCA). Angioplasty is a minimally invasive treatment 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 portion of the shaft, and an inflation lumen communicating with the balloon and through which a fluid for inflating or deflating the balloon can flow. The balloon is inserted into a blood vessel in a deflated state and delivered through the blood vessel to the stenotic site. After the balloon has reached the stenotic site, the inflation and deflation of the balloon are controlled by introducing or expelling fluid 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 including 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.

[0005] US Patent Application Publication No. 2012 / 0209375

[0006] In the balloon catheter described in Patent Document 1, adjacent outer balloon members are spaced apart, so when the outer balloon member is pressed against the stenotic area during dilation, it shifts circumferentially relative to the inner balloon member, which is thought to prevent sufficient dilation of the stenotic area. Furthermore, to dilate a stenotic area, a balloon with a large diameter and high pressure resistance is required. Furthermore, increasing the diameter of the balloon during dilation also increases the diameter of the balloon in its folded state during deflation, which causes it to come into contact with the inner wall of the blood vessel during insertion, making it difficult to insert into the blood vessel.

[0007] Blood vessel stenosis can also occur in the aortic valve, for example. When aortic valve stenosis occurs, the aortic valve is removed and a new bioprosthetic valve is implanted. However, implanted bioprosthetic valves deteriorate over time and require replacement every 5 to 10 years. When a surgically implanted bioprosthetic valve (artificial valve) deteriorates and a new bioprosthetic valve (artificial valve) is implanted via a catheter, the valve orifice area may become narrower. Therefore, the size of the new bioprosthetic valve must be smaller than the deteriorated bioprosthetic valve, which reduces blood flow, creates a pressure gradient across the bioprosthetic valve, and places a strain on the heart. Therefore, it is thought that deforming or destroying the existing bioprosthetic valve would allow for the implantation of a larger bioprosthetic valve. Therefore, the development of a larger-diameter balloon is required to deform or destroy the deteriorated bioprosthetic valve. Furthermore, the development of a high-pressure balloon is also required. Furthermore, blood perfusion across the balloon is desirable during such procedures.

[0008] An object of the present invention is to provide a balloon catheter (hereinafter sometimes referred to as a first balloon catheter or a second balloon catheter) having a large-diameter, high-pressure-resistant balloon. Another object of the present invention is to provide a balloon catheter (hereinafter sometimes referred to as a third balloon catheter) having a balloon that is easy to insert into a blood vessel, expands to a large diameter, and has a perfusion function when expanded. Another object of the present invention is to provide a method for expanding the balloon in a balloon catheter.

[0009] A first balloon catheter and a balloon inflation method according to an embodiment of the present invention are as follows. [1-1] A balloon catheter including 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 composed of a plurality of second balloons arranged in a circumferential direction around the outer periphery of the first balloon, wherein adjacent second balloons constituting the balloon group are in contact with each other when the first balloon and the balloon group are inflated. [1-2] A balloon catheter according to [1-1], wherein the balloon group is in contact with the outer periphery of the first balloon when the first balloon and the balloon group are inflated. [1-3] A balloon catheter according to [1-1] or [1-2], wherein the second balloons constituting the balloon group all have the same maximum outer diameter when the first balloon and the balloon group are inflated, and the maximum outer diameter of the second balloon is the same as the maximum outer diameter of the first balloon. [1-4] The balloon catheter according to [1-1] or [1-2], wherein the second balloons constituting the balloon group have two or more different maximum outer diameters when the balloon group is inflated. [1-5] The balloon catheter according to [1-4], wherein two second balloons with different maximum outer diameters are arranged circumferentially around the first balloon when the first balloon and the balloon group are inflated, and the second balloon with the smaller maximum outer diameter is sandwiched between the second balloons with the larger maximum outer diameter. [1-6] The balloon catheter according to [1-1] or [1-2], wherein the second balloons constituting the balloon group all have the same maximum outer diameter when the first balloon and the balloon group are inflated, and the maximum outer diameter of the second balloon is different from the maximum outer diameter of the first balloon. [1-7] The balloon catheter according to [1-6], wherein the maximum outer diameter of the second balloon constituting the balloon group is smaller than the maximum outer diameter of the first balloon.[1-8] The balloon catheter according to [1-7], wherein the shaft has a first inflation lumen and a plurality of second inflation lumens extending in a 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 constituting the balloon group, the plurality of second inflation lumens communicate with a single proximal second inflation lumen proximal to the connection points 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. [1-9] The balloon catheter according to [1-8], wherein a sum of the cross-sectional areas of the plurality of second inflation lumens 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. [1-10] The balloon catheter according to [1-8] or [1-9], wherein the smallest cross-sectional area 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. [1-11] The balloon catheter according to any of [1-1] to [1-6], wherein the shaft has a first inflation lumen and multiple second inflation lumens extending in the longitudinal direction of the shaft, the first inflation lumen connected to the first balloon, and the multiple second inflation lumens connected to each of the multiple second balloons that make up the balloon group. [1-12] The balloon catheter according to [1-11], wherein the multiple second inflation lumens communicate with a single proximal second inflation lumen proximal to the connection position with the multiple second balloons.[1-13] The balloon catheter of [1-12], 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. [1-14] The balloon catheter of [1-13], 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 sum of the cross-sectional areas of the second inflation lumens in a direction perpendicular to the longitudinal direction. [1-15] The balloon catheter of [1-13] or [1-14], 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 of ​​the second inflation lumens in a direction perpendicular to the longitudinal direction. [1-16] A balloon catheter according to any one of [1-1] to [1-15], which is used for expanding an aortic valve, deforming a biological valve placed in the heart, or destroying the biological valve. [1-17] A method for expanding the balloon of the balloon catheter according to any one of [1-3] to [1-6], in which a pressurizer expands the first balloon and then expands the group of balloons. [1-18] A method for expanding the balloon of the balloon catheter according to [1-7], in which a pressurizer expands the group of balloons and then expands the first balloon.

[0010] A second balloon catheter according to an embodiment of the present invention is as follows. [2-1] A balloon catheter including 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 composed of a plurality of second balloons arranged in a circumferential direction around the first balloon, wherein the pressure resistance value P2 of the second balloon is greater than the pressure resistance value P1 of the first balloon. [2-2] The balloon catheter according to [2-1], wherein the ratio of the pressure resistance value P2 to the pressure resistance value P1 (P2 / P1) is 1.2 to 16. [2-3] The balloon catheter according to [2-1] or [2-2], wherein adjacent second balloons constituting the balloon group are in contact with each other when the first balloon and the balloon group are inflated. [2-4] The balloon catheter according to any of [2-1] to [2-3], wherein the first balloon and the balloon group are in contact with the outer circumferential surface of the first balloon when inflated. [2-5] The balloon catheter according to any one of [2-1] to [2-4], wherein the maximum outer diameter of the second balloons constituting the balloon group is the same when the first balloon and the balloon group are inflated, and the maximum outer diameter of the second balloon is the same as the maximum outer diameter of the first balloon. [2-6] The balloon catheter according to any one of [2-1] to [2-4], wherein the maximum outer diameter of the second balloons constituting the balloon group is two or more different when the balloon group is inflated. [2-7] The balloon catheter according to [2-6], wherein two second balloons with different maximum outer diameters when the first balloon and the balloon group are inflated are arranged circumferentially around the outer periphery 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 diameters. [2-8] The balloon catheter according to any one of [2-1] to [2-4], wherein, when the first balloon and the balloon group are inflated, 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.[2-9] The balloon catheter according to [2-8], wherein a maximum outer diameter of a second balloon constituting the balloon group is smaller than a maximum outer diameter of the first balloon. [2-10] The balloon catheter according to [2-9], wherein the shaft has a first inflation lumen and a plurality of second inflation lumens extending in a 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 constituting the balloon group, the plurality of second inflation lumens communicate with a single proximal second inflation lumen proximal to positions of connection 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 larger than a cross-sectional area S1 of the first inflation lumen in a direction perpendicular to the longitudinal direction. [2-11] The balloon catheter according to any one of [2-1] to [2-8], 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 being connected to the first balloon, and the plurality of second inflation lumens being connected to a plurality of second balloons constituting the balloon group. [2-12] The balloon catheter according to any one of [2-1] to [2-11], wherein the balloon catheter is used to dilate an aortic valve, deform a biological valve placed in the heart, or destroy the biological valve.

[0011] A third embodiment of the present invention relates to a balloon catheter as follows. [3-1] A balloon catheter including 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 composed of a plurality of second balloons arranged in a circumferential direction around the first balloon, wherein the pressure resistance value P1 of the first balloon is greater than the pressure resistance value P2 of the second balloon. [3-2] The balloon catheter according to [3-1], wherein the ratio of the pressure resistance value P2 to the pressure resistance value P1 (P2 / P1) is 0.08 to 0.9. [3-3] The balloon catheter according to [3-1] or [3-2], wherein adjacent second balloons constituting the balloon group are in contact with each other when the first balloon and the balloon group are inflated. [3-4] The balloon catheter according to any one of [3-1] to [3-3], wherein the balloon group is in contact with the outer circumferential surface of the first balloon when the first balloon and the balloon group are inflated. [3-5] The balloon catheter according to any one of [3-1] to [3-4], wherein the maximum outer diameter of the second balloons constituting the balloon group is the same when the first balloon and the balloon group are inflated, and the maximum outer diameter of the second balloon is the same as the maximum outer diameter of the first balloon. [3-6] The balloon catheter according to any one of [3-1] to [3-4], wherein the maximum outer diameter of the second balloons constituting the balloon group is two or more different when the balloon group is inflated. [3-7] The balloon catheter according to [3-6], wherein two second balloons with different maximum outer diameters when the first balloon and the balloon group are inflated are arranged circumferentially around the outer periphery 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 diameters. [3-8] The balloon catheter according to any one of [3-1] to [3-4], wherein, when the first balloon and the balloon group are inflated, 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.[3-9] The balloon catheter according to [3-8], wherein a maximum outer diameter of a second balloon constituting the balloon group is smaller than a maximum outer diameter of the first balloon. [3-10] The balloon catheter according to [3-9], wherein the shaft has a first inflation lumen and a plurality of second inflation lumens extending in a longitudinal direction of the shaft, the first inflation lumen is connected to the first balloon, the second inflation lumens are connected to each of the second balloons constituting the balloon group, the second inflation lumens are connected to a single proximal second inflation lumen proximal to positions where the second inflation lumens are connected to the second balloons, and a cross-sectional area S2 of the proximal second inflation lumen in a direction perpendicular to the longitudinal direction is larger than a cross-sectional area S1 of the first inflation lumen in a direction perpendicular to the longitudinal direction. [3-11] The balloon catheter according to any one of [3-1] to [3-8], 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 being connected to the first balloon, and the plurality of second inflation lumens being connected to a plurality of second balloons constituting the balloon group. [3-12] The balloon catheter according to any one of [3-1] to [3-11], wherein the balloon catheter is used to dilate an aortic valve, deform a biological valve placed in the heart, or destroy the biological valve.

[0012] The first balloon catheter includes a first balloon and a balloon group consisting of a plurality of second balloons arranged circumferentially around the first balloon. Therefore, by inflating both the first balloon and the balloon group, the outer diameter of the balloon of the balloon catheter including the first balloon and the balloon group can be increased. Furthermore, when the first balloon and the balloon group are inflated, adjacent second balloons constituting the balloon group are in contact with each other, so that even if the second balloon is pressed against the stricture, the first balloon is less likely to shift circumferentially around the stricture. As a result, the balloon group can reliably dilate the stricture. Furthermore, when the first balloon and the balloon group are inflated, adjacent second balloons constituting the balloon group are in contact with each other, so that even if the pressure when inflating the second balloon is increased, the second balloons mutually suppress their expansion, thereby increasing the pressure resistance and increasing the hardness (expansion force) of the second balloon.

[0013] The second balloon catheter includes a first balloon and a balloon group consisting of multiple second balloons arranged circumferentially around the first balloon. By inflating both the first balloon and the balloon group, the outer diameter of the balloon of the balloon catheter including the first balloon and the balloon group can be increased. Furthermore, the second balloon has a pressure resistance value P2 greater than the pressure resistance value P1 of the first balloon. Therefore, when the first balloon and the balloon group are inflated, the second balloon is less likely to deform even if stress concentrates on the balloon group, resulting in high pressure resistance and increased destructive force. Furthermore, the second balloon has a pressure resistance value P1 smaller than the pressure resistance value P2 of the first balloon. Therefore, when the balloon group consisting of multiple second balloons is inflated, the first balloon acts as a cushioning material, preventing the second balloon from shifting circumferentially and radially from the first balloon. This prevents the balloon from inflating undesired areas, thereby improving safety.

[0014] The third balloon catheter includes a first balloon and a balloon group consisting of multiple second balloons arranged circumferentially around the first balloon. Therefore, by inflating both the first balloon and the balloon group, the outer diameter of the balloon of the balloon catheter including the first balloon and the balloon group can be increased. Furthermore, since the pressure resistance value P1 of the first balloon is greater than the pressure resistance value P2 of the second balloon, the second balloon can be easily inflated uniformly around the first balloon. Furthermore, since the pressure resistance value P2 of the second balloon is smaller than the pressure resistance value P1 of the first balloon, the second balloon is softer than the first balloon, allowing the balloon catheter to be inserted into a blood vessel without damaging the blood vessel, ensuring minimal invasiveness. Furthermore, since the pressure resistance value P2 of the second balloon is smaller than the pressure resistance value P1 of the first balloon, when the balloon group is pressed against the stenotic site when the first balloon and the balloon group are inflated, a gap is created between the balloon group and the stenotic site, improving perfusion function.

[0015] Fig. 1 is a side view (partially see-through) of a balloon catheter. Fig. 2 is a side view (partially see-through) of a balloon of the balloon catheter. Fig. 3 is a cross-sectional view of the balloon shown in Fig. 2 taken along line II. Fig. 4 is a cross-sectional view of a balloon different from the balloon shown in Fig. 2. Fig. 5 is a cross-sectional view of a balloon different from the balloon shown in Fig. 2. Fig. 6 is a longitudinal cross-sectional view of the shaft of a balloon catheter.

[0016] The first balloon catheter has a shaft extending longitudinally from the proximal side to the distal side, a first balloon disposed at a distal portion of the shaft, and a balloon group consisting of a plurality of second balloons arranged in a circumferential direction around the first balloon, wherein adjacent second balloons of the balloon group are in contact with each other when the first balloon and the balloon group are inflated.The second balloon catheter has a shaft extending longitudinally from the proximal side to the distal side, a first balloon disposed at a distal portion of the shaft, and a balloon group consisting of a plurality of second balloons arranged in a circumferential direction around the first balloon, wherein the pressure resistance value P2 of the second balloon is greater than the pressure resistance value P1 of the first balloon. The third balloon catheter has 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 arranged in a circumferential direction around the first balloon, and is characterized in that the pressure resistance value P1 of the first balloon is greater than the pressure resistance value P2 of the second balloon. The first to third balloon catheters will be described below. Note that the first to third balloon catheters will sometimes be collectively referred to as "balloon catheter" or "balloon catheter 1" without distinction.

[0017] The following describes in detail balloon catheters according to embodiments of the present invention with reference to the drawings. However, the present invention is not limited to the illustrated examples, and modifications may be made within the scope of the above-mentioned and below-mentioned spirit, and all such modifications are within the technical scope of the present invention. For convenience, hatching and symbols may be omitted in the drawings. In such cases, reference should be made to the specification and other drawings. Furthermore, the dimensions of various components in the drawings may differ from their actual dimensions, as priority is given to aiding understanding of the features of the present invention.

[0018] 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.

[0019] 1 and 2, the balloon catheter 1 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 circumferential direction around the outer periphery of the first balloon A. In this specification, the balloons of the balloon catheter 1, including the first balloon A and the plurality of second balloons that make up the balloon group B, may be simply referred to as "balloon 2."

[0020] The shaft 10 has a longitudinal direction x, a radial direction y connecting the centroid of the outer edge of the shaft 10 to 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 direction opposite the proximal side, i.e., the direction toward the patient, 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).

[0021] Members and parts other than the shaft 10 also have longitudinal, radial, 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 assuming that all members and parts have the same longitudinal, radial, and circumferential directions as the longitudinal direction x, radial direction y, and circumferential direction z of the shaft 10.

[0022] 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 lumen of the shaft 10, and can be deflated by discharging the introduced fluid. To control the expansion and deflation of the first balloon A and the second balloon, an indeflator (a balloon pressurizer) can be used to introduce or discharge the fluid. For example, a mixture of a contrast agent and physiological saline is used as the fluid. The fluid may also be a pressurized fluid pressurized by a pump or the like.

[0023] The balloon catheter 1 shown in Figures 2 and 3 is composed of one first balloon A and six second balloons, which constitute a balloon group B. For ease of explanation, two of the six second balloons are labeled b1 and b2 in Figures 2 and 3. 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.

[0024] 2 and 3, the balloon catheter 1 has a balloon group B consisting of multiple second balloons arranged around the outer periphery of the first balloon A in the circumferential direction z, and the outer diameter of the balloon 2 can be increased by inflating both the first balloon A and the balloon group B. As a result, the stenotic area can be dilated reliably.

[0025] As shown in Figures 2 and 3 , in the first balloon catheter 1, when the first balloon A and balloon group B are inflated, adjacent second balloons b1 and b2 of the multiple second balloons constituting balloon group B are in contact with each other. The contact between adjacent second balloons b1 and b2 suppresses the expansion of each other, thereby increasing the pressure resistance of the balloon group B, thereby increasing the expansion force of the balloon group B. Furthermore, the contact between adjacent second balloons b1 and b2 reduces the likelihood of the second balloons coming into contact with the stricture site, thereby preventing the first balloon A from shifting in the circumferential direction z, thereby ensuring reliable expansion of the stricture site. When the first balloon A and balloon group B are inflated, it is sufficient that at least one pair of adjacent second balloons of the multiple second balloons constituting balloon group B are in contact with each other. It is preferable that two or more pairs of adjacent second balloons are in contact with each other, and it is more preferable that all adjacent second balloons are in contact with each other. All adjacent second balloons are in contact with each other, so that the second balloons can be uniformly inflated.

[0026] In the second balloon catheter 1, the pressure resistance value P2 of the second balloon is greater than the pressure resistance value P1 of the first balloon A (P2 > P1). Because the pressure resistance value P2 of the second balloon is greater than the pressure resistance value P1 of the first balloon A, the balloon group B, which is composed of multiple second balloons, acts as a reinforcing layer for the first balloon A, improving the pressure resistance of the balloon group B. Furthermore, because the pressure resistance value P2 of the second balloon is greater than the pressure resistance value P1 of the first balloon A, the second balloon is more likely to penetrate into the blood vessel, thereby reducing slippage during balloon inflation in the longitudinal direction of the shaft 10. Furthermore, because the pressure resistance value P1 of the first balloon A is smaller than the pressure resistance value P2 of the second balloon A, the first balloon A acts as a cushioning material during inflation of the multiple second balloons, preventing the second balloon from shifting in the radial direction y and circumferential direction z of the first balloon A. This prevents the balloon group B from inflating areas other than the desired location, thereby improving safety.

[0027] In the second balloon catheter 1, the ratio (P2 / P1) of the pressure resistance value P2 of the second balloon to the pressure resistance value P1 of the first balloon A may be any value greater than 1, preferably 1.2 to 16. A ratio (P2 / P1) of 1.2 or greater increases the pressure resistance of balloon group B, allowing balloon group B to effectively function as a reinforcing layer for first balloon A and thereby increasing the pressure resistance of balloon group B. The ratio (P2 / P1) is more preferably 1.5 or greater, and even more preferably 2 or greater. However, if the ratio (P2 / P1) is too large, the difference in pressure resistance between the first balloon A and balloon group B becomes too large, causing the first balloon A to be crushed by balloon group B and causing the second balloon to shift in the radial direction y of the first balloon A, making it difficult to uniformly inflate balloon group B. Therefore, the ratio (P2 / P1) is preferably 15 or less, more preferably 13 or less, and even more preferably 10 or less.

[0028] The pressure resistance value P1 of the first balloon A in the second balloon catheter 1 is preferably, for example, 4 to 30 atm, more preferably 6 atm or more, even more preferably 8 atm or more, more preferably 28 atm or less, and even more preferably 25 atm or less.The pressure resistance value P2 of the second balloon in the second balloon catheter 1 is preferably, for example, 24 to 60 atm, more preferably 27 atm or more, even more preferably 30 atm or more, more preferably 50 atm or less, and even more preferably 40 atm or less.

[0029] The pressure resistance values ​​of the first balloon A and the second balloon of the second balloon catheter 1 can be measured by the following procedure. A water bath with the water temperature adjusted to 37°C ± 1°C using a heater is prepared, and the first balloon A and the second balloon of the balloon catheter 1 are immersed in the water bath. A leak tester is connected to the catheter, the heater is turned off, and pressure is applied until the balloons burst. The pressure at which the balloons burst is measured and used as the pressure resistance value. The balloons are pressurized under conditions of an initial introduction pressure of 2.0 atm and a rate of 0.2 atm per second. The maximum pressure during pressurization is 40 atm. The pressure resistance values ​​are measured for each of the first balloon A and the second balloon. The pressure resistance value P2 of the second balloon is determined by measuring the pressure resistance values ​​of at least three second balloons selected at random from a plurality of second balloons, and averaging these values ​​to determine the pressure resistance value P2 of the second balloon. The pressure resistance value P2 of the second balloon may be the average value of the pressure resistance values ​​of 10 second balloons, or may be the average value of the pressure resistance values ​​of 20 second balloons.

[0030] In the second balloon catheter 1, the film thickness of the first balloon A and the film thickness of the second balloon may be the same, but it is preferable that the film thickness of the second balloon be thicker than the film thickness of the first balloon A. By increasing the film thickness of the second balloon, it is possible to easily make the pressure resistance value P2 of the second balloon greater than the pressure resistance value P1 of the first balloon A. The film thickness of the first balloon A and the film thickness of the second balloon may be measured at the straight tube portion 23 of the first balloon A and the straight tube portion 23 of the second balloon.

[0031] 2 and 3 , in the second balloon catheter 1, it is preferable that, during inflation of the first balloon A and the balloon group B, adjacent second balloons b1 and b2 of the multiple second balloons constituting the balloon group B are in contact with each other. By having adjacent second balloons b1 and b2 in contact with each other, the second balloons suppress each other's inflation, thereby increasing the pressure resistance and enhancing the inflation force of the balloon group B. Furthermore, because adjacent second balloons b1 and b2 are in contact with each other, even if the second balloons come into contact with the stenotic region, the second balloons are less likely to shift in the circumferential direction z around the outer periphery of the first balloon A, thereby ensuring reliable inflation of the stenotic region.

[0032] During inflation of the first balloon A and balloon group B in the second balloon catheter 1, at least one pair of adjacent second balloons of the multiple second balloons constituting balloon group B need to be in contact with each other, preferably two or more pairs of adjacent second balloons need to be in contact with each other, and more preferably all adjacent second balloons need to be in contact with each other. Having all adjacent second balloons in contact with each other allows the second balloons to be inflated uniformly.

[0033] In the third balloon catheter 1, the pressure resistance value P1 of the first balloon A is greater than the pressure resistance value P2 of the second balloon (P1 > P2). Because the pressure resistance value P1 of the first balloon A is greater than the pressure resistance value P2 of the second balloon, the second balloon is more easily inflated uniformly around the first balloon A as the central axis. Furthermore, because the pressure resistance value P2 of the second balloon is smaller than the pressure resistance value P1 of the first balloon A, the second balloon is softer than the first balloon A, allowing the balloon catheter to be inserted into a blood vessel without damaging the blood vessel. Furthermore, because the pressure resistance value P2 of the second balloon is smaller than the pressure resistance value P1 of the first balloon A, when the first balloon A and the balloon group B are inflated, if the balloon group B is pressed against the stenotic area, a gap is created between the balloon group B and the stenotic area, improving perfusion function.

[0034] In the third balloon catheter 1, the ratio (P2 / P1) of the pressure resistance value P2 of the second balloon to the pressure resistance value P1 of the first balloon A may be less than 1, preferably 0.03 to 0.8. A ratio (P2 / P1) of 0.8 or less facilitates uniform expansion of the second balloon in the circumferential direction around the first balloon A as the central axis. This also improves the ease of insertion of the balloon catheter into a blood vessel and its perfusion function. A ratio (P2 / P1) of 0.7 or less is more preferable, and 0.6 or less is even more preferable. However, if the ratio (P2 / P1) is too small, the pressure resistance value of the second balloon decreases, making the second balloon more susceptible to damage. Therefore, the ratio (P2 / P1) is preferably 0.03 or more, more preferably 0.1 or more, and even more preferably 0.2 or more.

[0035] The pressure resistance value P1 of the first balloon A in the third balloon catheter 1 is preferably, for example, 28 to 60 atm, more preferably 30 atm or more, even more preferably 32 atm or more, more preferably 50 atm or less, and even more preferably 40 atm or less. The pressure resistance value P2 of the second balloon is preferably, for example, 2.2 to 45 atm, more preferably 3 atm or more, even more preferably 6 atm or more, more preferably 30 atm or less, and even more preferably 25 atm or less.

[0036] The pressure resistance values ​​of the first balloon A and the second balloon of the third balloon catheter 1 can be measured by the following procedure. A water bath with the water temperature adjusted to 37°C ± 1°C using a heater is prepared, and the first balloon A and the second balloon of the balloon catheter 1 are immersed in the water bath. A leak tester is connected to the catheter, the heater is turned off, and pressure is applied until the balloons burst. The pressure at which the balloons burst is measured and used as the pressure resistance value. The balloons are pressurized under conditions of an initial introduction pressure of 2.0 atm and a rate of 0.2 atm per second. The maximum pressure during pressurization is 40 atm. The pressure resistance values ​​are measured for each of the first balloon A and the second balloon. The pressure resistance value P2 of the second balloon is determined by measuring the pressure resistance values ​​of at least three second balloons selected at random from a plurality of second balloons, and averaging these values ​​to determine the pressure resistance value P2 of the second balloon. The pressure resistance value P2 of the second balloon may be the average value of the pressure resistance values ​​of 10 second balloons, or may be the average value of the pressure resistance values ​​of 20 second balloons.

[0037] In the third balloon catheter 1, the film thickness of the first balloon A and the film thickness of the second balloon may be the same, but it is preferable that the film thickness of the first balloon A be thicker than the film thickness of the second balloon. By increasing the film thickness of the first balloon A, the pressure resistance value P1 of the first balloon A can be easily made greater than the pressure resistance value P2 of the second balloon. The film thickness of the first balloon A and the film thickness of the second balloon may be measured at the straight tube portion 23 of the first balloon A and the straight tube portion 23 of the second balloon.

[0038] 2 and 3 , in the third balloon catheter 1, it is preferable that, during inflation of the first balloon A and the balloon group B, adjacent second balloons b1 and b2 of the multiple second balloons constituting the balloon group B are in contact with each other. By having adjacent second balloons b1 and b2 in contact with each other, the second balloons suppress each other's inflation, thereby increasing the pressure resistance and enhancing the inflation force of the balloon group B. Furthermore, because adjacent second balloons b1 and b2 are in contact with each other, even if the second balloons come into contact with the stenotic region, they are less likely to shift in the circumferential direction z around the outer periphery of the first balloon A, thereby ensuring reliable inflation of the stenotic region.

[0039] During inflation of the first balloon A and balloon group B in the third balloon catheter 1, at least one pair of adjacent second balloons of the multiple second balloons constituting balloon group B need only be in contact with each other, preferably two or more pairs of adjacent second balloons need be in contact with each other, and more preferably all adjacent second balloons need be in contact with each other. Having all adjacent second balloons in contact with each other allows the second balloons to be inflated uniformly.

[0040] During inflation of the first balloon A and balloon group B, the second balloon constituting balloon group B may not be in contact with the outer circumferential surface of the first balloon A. However, it is preferable that at least one of the multiple second balloons constituting balloon group B be in contact with the outer circumferential surface of the first balloon A. By having at least one of the multiple second balloons in contact with the outer circumferential surface of the first balloon A, even when 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, making it less likely for the first balloon A to shift in the radial direction y, thereby ensuring reliable inflation of the narrowed portion. It is more preferable that all of the multiple second balloons constituting balloon group B be in contact with the outer circumferential surface of the first balloon A. By having all of the multiple second balloons in contact with the outer circumferential surface of the first balloon A, the first balloon A and the second balloon mutually inflate even when the second balloon is pressed against the narrowed portion, thereby enabling balloon group B to withstand high pressure.

[0041] The number of second balloons constituting balloon group B is preferably three or more, more preferably four or more, and even more preferably five or more. Setting the lower limit of the number of second balloons constituting balloon group B within the above range makes it easier for balloon group B to surround the outer periphery of first balloon A, making it easier for balloon group B to suppress the expansion of first balloon A. As a result, when fluid is introduced into both first balloon A and balloon group B, first balloon A and balloon group B mutually suppress the expansion of each other, making balloon 2 more pressure-resistant and increasing the hardness of balloon 2, thereby improving the expansion force. Furthermore, because first balloon A and balloon group B mutually suppress the expansion of each other, balloon 2 is less likely to expand. Therefore, even when high pressure is applied to balloon 2, over-expansion of balloon 2 is suppressed, preventing balloon 2 from expanding beyond the intended outer diameter. This reduces damage to intravascular lumens such as the aortic valve, 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.

[0042] When the first balloon A and the balloon group B are inflated, the maximum outer diameter of the circumscribed circle of the balloon 2 is not particularly limited, but is preferably in the range of 5 mm to 60 mm, for example.

[0043] The relationship between the maximum outer diameter Da of the first balloon A and the maximum outer diameter of the second balloon constituting balloon group B preferably satisfies any one of the following conditions (1) to (3): (1) When the first balloon A and balloon group B are inflated, the second balloons constituting 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 Da 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 balloon group B are inflated, the second balloons constituting 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 Da of the first balloon A.

[0044] The maximum outer diameter Da of the first balloon A refers to the maximum circular equivalent 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 circular equivalent diameter of the second balloon in a cross section perpendicular to the longitudinal direction x of the second balloon.

[0045] Item (1) will be explained using Figure 3. As shown in Figure 3, when the first balloon A and balloon group B are inflated, the second balloons constituting 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 Da of the first balloon A. This facilitates balancing the force exerted by the first balloon A to expand and the force exerted by the second balloon to inhibit the expansion of the first balloon A. As a result, the hardness of the first balloon A and balloon group B is increased, making it easier to increase the expansion force of balloon group B and ensure uniform expansion of the stenotic area.

[0046] 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 balloons 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 similar, specifically, that the maximum outer diameter of the second balloon with the largest maximum outer diameter among the second balloons constituting balloon group B is 100% to 110% of the maximum outer diameter of the second balloon with the smallest maximum outer diameter among the second balloons constituting balloon group B. The fact that the maximum outer diameter Da of the first balloon A is the same as the maximum outer diameters of the second balloons constituting balloon group B means that the maximum outer diameter Da of the first balloon A and the maximum outer diameters of the second balloons constituting balloon group B are similar, specifically, that the maximum outer diameter Da of the first balloon A is 90% to 110% of the maximum outer diameter (e.g., the average value) of the second balloons.

[0047] (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 , taken at a position corresponding to FIG. 3 . As shown in FIG. 4 , when balloon group B is inflated, the second balloons constituting balloon group B have two or more different maximum outer diameters. Therefore, multiple second balloons with different maximum outer diameters are arranged in the circumferential direction z around the outer periphery of first balloon A. Therefore, the second balloons b11 and b12 of balloon group B with the larger maximum outer diameters contact the inner wall of the blood vessel, while the second balloons b13 and b14 of balloon group B with the smaller maximum outer diameters do not contact the inner wall of the blood vessel. This facilitates the creation of a space between the inner wall of the blood vessel and the second balloons b13 and b14 that do not contact the inner wall, thereby allowing blood to perfuse. Furthermore, since the second balloons b11 and b12 of balloon group B with the larger maximum outer diameters contact the inner wall of the blood vessel, the number of second balloons in balloon group B that contact the inner wall of the blood vessel is limited. This reduces the number of contact points between the second balloons and the inner wall of the blood vessel, thereby concentrating the stress applied by the second balloons to the inner wall of the blood vessel. As a result, the narrowed area can be dilated reliably.

[0048] When the number of second balloons constituting balloon group B is at least three, and when the first balloon A and 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 be sandwiched between the second balloons b11 and b12 with the larger maximum outer diameter, as shown in Figure 4. By sandwiching the second balloon with the smaller maximum outer diameter between the second balloons with the larger maximum outer diameters 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 that are not in contact with the inner wall of the blood vessel are dispersed in the circumferential direction z around the outer periphery of the first balloon A, thereby enabling stable blood perfusion.

[0049] 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.

[0050] 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 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 with the larger maximum outer diameter to the maximum outer diameter Db13 of the second balloon b13 with the smaller maximum outer diameter is, for example, preferably greater than 1 and not greater than 5, more preferably 1.1 or greater, even more preferably greater than 1.1, particularly preferably 2 or greater, most preferably 2.5 or greater, and more preferably 4.5 or less, even more preferably 4 or less.

[0051] 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 25 mm or less).

[0052] (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 balloon group B are inflated, the second balloons constituting balloon group B all have the same maximum outer diameter. However, because the second balloons have different maximum outer diameters from the maximum outer diameter Da of the first balloon A, the first balloon A and second balloons with different maximum outer diameters can be appropriately combined to adjust the maximum outer diameter of balloon group B, making it easier to adjust the maximum outer diameter of balloon group B. Having the same maximum outer diameter of the second balloons constituting balloon group B means that the second balloons constituting balloon group B have similar maximum outer diameters. Specifically, this means that the maximum outer diameter of the second balloon with the largest maximum outer diameter among the second balloons constituting balloon group B is 100% or more but 110% or less of the maximum outer diameter of the second balloon with the smallest maximum outer diameter among the second balloons constituting balloon group B.

[0053] 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 Da 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 Da of the first balloon A, the first balloon A can be inflated at a high pressure, thereby reliably dilating the stenotic area.

[0054] When the maximum outer diameter of the second balloons constituting balloon group B is larger than the maximum outer diameter Da 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 1.1 or greater, even more preferably greater than 1.1, particularly preferably 1.2 or greater, and more preferably 4 or less, even more preferably 3 or less.

[0055] When the maximum outer diameter of the second balloons constituting balloon group B is larger than the maximum outer diameter Da of the first balloon A, it is preferable that the maximum outer diameter Da of the first balloon A is, for example, 3 mm to 5 mm, and it is preferable that the maximum outer diameter Db21 of the second balloon b21 is, for example, 3.1 mm to 13.5 mm (particularly, greater than 3.3 mm and equal to or less than 13.5 mm).

[0056] When the maximum outer diameter of the second balloons constituting balloon group B is smaller than the maximum outer diameter Da 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.

[0057] If the maximum outer diameter of the second balloons constituting balloon group B is smaller than the maximum outer diameter Da of the first balloon A, it is preferable that the maximum outer diameter Da of the first balloon A is, for example, 3 mm to 20 mm, and the maximum outer diameter Db21 of the second balloon b21 is, for example, 1.0 mm to 5 mm.

[0058] 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 make up the balloon group B.

[0059] The shaft 10 includes 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. This allows fluid to be introduced into or discharged from each lumen using a balloon pressurizer connected to the first inflation lumen and a balloon pressurizer connected to each of the plurality of second inflation lumens. This allows the timing of inflation and deflation of the first balloon A and the plurality of second balloons to be individually controlled. Furthermore, the inflation pressures of the first balloon A and the plurality of second balloons can be individually controlled. As a result, various treatments and situations can be accommodated.

[0060] Preferably, the multiple second inflation lumens communicate with one proximal second inflation lumen proximal to the connection positions with the multiple second balloons. This configuration will be described with reference to Figure 6. Figure 6 is a cross-sectional view of the shaft 10 of the balloon catheter 1 in the longitudinal direction x, with the left side of the figure representing the proximal side (operator side) and the right side representing the distal side (affected area side). As shown in Figure 6, the shaft 10 has a first inflation lumen La, a second inflation lumen Lb1, and a second inflation lumen Lb2. In Figure 6, a guidewire tube 40 is disposed in the first inflation lumen La, and the guidewire tube 40 has a guidewire lumen L40. When a first balloon A (not shown) is connected to the first inflation lumen La, a second balloon b1 (not shown) is connected to the second inflation lumen Lb1, and a 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 a single proximal second inflation lumen Lb proximal to the connection points of the second balloons b1, b2. Because the proximal second inflation lumen Lb communicates with multiple second inflation lumens Lb1, Lb2, fluid introduced using a 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 into the second balloons b1, b2, thereby simultaneously inflating the second balloons b1, b2. In addition, when discharging fluid from the second balloons b1 and b2, the fluid can be discharged through the second inflation lumens Lb1 and Lb2 using a balloon pressurizer connected to the proximal second inflation lumen Lb, thereby allowing the second balloons b1 and b2 to be deflated simultaneously.

[0061] When the second inflation lumens communicate with one proximal second inflation lumen Lb proximal to the connection points 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. By making the cross-sectional area S2 larger than the cross-sectional area S1, the balloon group B expands before the first balloon A, allowing the balloon group B to expand uniformly.

[0062] When cross-sectional area S2 is larger than 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 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 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 cross-sectional area S1, balloon B expands before first balloon A, thereby achieving uniform expansion of balloon B. When the smallest cross-sectional area of ​​the second inflation lumens in a direction perpendicular to the longitudinal direction x is larger than cross-sectional area S1, balloon B expands before first balloon A, thereby achieving uniform expansion of balloon B.

[0063] The balloon catheter 1 preferably includes a shaft 10 having a first inflation lumen La and a plurality of second inflation lumens extending in the longitudinal direction x of the shaft 10, a first balloon A connected to the first inflation lumen La, and a second balloon constituting a balloon group B connected to each of the plurality of second inflation lumens. A pressurizer for introducing or discharging a fluid for inflating or deflating the first balloon A is connected to the first inflation lumen La connected to the first balloon A, and a pressurizer for introducing or discharging a fluid for inflating or deflating the second balloon is connected to the second inflation lumen connected to the second balloon constituting the balloon group B. This allows the fluid for inflating or deflating the first balloon A and the second balloon A to be introduced or discharged at different times from 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 inflated or deflated at different times. For example, by first introducing fluid using a balloon pressurizer connected to the first inflation lumen La and then introducing fluid into each of the multiple second inflation lumens using balloon pressurizers connected to each of the multiple second inflation lumens, the first balloon A can be inflated first, followed by the multiple second balloons. Also, by connecting pressurizers to the first inflation lumen La and each of the multiple second inflation lumens, the inflation pressures of the first balloon A and the multiple second balloons can be individually controlled. As a result, various treatments and situations can be accommodated.

[0064] When each of the plurality of second inflation lumens is connected to a second balloon that constitutes balloon group B, the plurality of second inflation lumens preferably communicate with one proximal second inflation lumen Lb proximal to the connection points with the plurality of second balloons. A pressurizer that introduces or discharges a fluid for inflating or deflating the second balloons is connected to the proximal second inflation lumen Lb, and when a fluid is introduced from the pressurizer, the fluid passes through the proximal second inflation lumen Lb and is introduced into each of the plurality of second inflation lumens at the same time, thereby allowing the plurality of second balloons to be inflated at the same time.

[0065] When multiple second inflation lumens communicate with one proximal second inflation lumen Lb proximal to the connection position with the second balloon, it is preferable that the cross-sectional area S1 of the first inflation lumen La in a direction perpendicular to the longitudinal direction x is the same as or larger than the cross-sectional area S2 of the proximal second inflation lumen Lb in a direction perpendicular to the longitudinal direction x. Having the cross-sectional area S1 equal to the cross-sectional area S2 allows the multiple second balloons and the first balloon A to be inflated simultaneously. Having the cross-sectional area S1 larger than the cross-sectional area S2 allows the first balloon A to be inflated before the multiple second balloons.

[0066] When cross-sectional area S1 is equal to or greater than cross-sectional area S2, cross-sectional area S1 is preferably 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. Having 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 allows the second balloons and first balloon A to be inflated simultaneously. Having 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 allows the first balloon A to be inflated before the second balloons.

[0067] When cross-sectional area S1 is the same as or larger than cross-sectional area S2, cross-sectional area S1 is preferably the same as or larger than the largest cross-sectional area of ​​the multiple second inflation lumens in a direction perpendicular to the longitudinal direction x. Having cross-sectional area S1 the same as the largest cross-sectional area of ​​the multiple second inflation lumens in a direction perpendicular to the longitudinal direction x allows the multiple second balloons and first balloon A to be inflated simultaneously. Having cross-sectional area S1 larger than the largest cross-sectional area of ​​the multiple second inflation lumens in a direction perpendicular to the longitudinal direction x allows the first balloon A to be inflated before the multiple second balloons.

[0068] The first balloon A and second balloon of the balloon catheter 1 preferably have a straight tube portion 23, a proximal tapered portion 22 located proximal to the straight tube portion 23, and a distal tapered portion 24 located distal to the straight tube portion 23, and may also have a proximal sleeve portion 21 located proximal to the proximal tapered portion 22 and a distal sleeve portion 25 located distal to the distal tapered portion 24.

[0069] During inflation 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 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. By making the length L1 of the first balloon A shorter than the length L2 of the second balloon b1, the portion where the first balloon A is present is more likely to be inflated to a greater extent than the portion where the first balloon A is not present. As a result, it is easier to apply pressure to the portion where the first balloon A is present, allowing for accurate application of pressure to the target location. Furthermore, since the portion where the first balloon A is not present is less likely to be inflated to a greater extent and therefore less likely to apply pressure, stress is less likely to be applied to portions other than the target location, thereby improving the minimally invasive nature of the balloon catheter 1.

[0070] 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 inflation 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 at least 20%, more preferably at least 25%, and even more preferably at least 30% 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 site using the balloon catheter 1, making it easier to dilate a stenotic area or destroy a biological valve, for example.

[0071] As shown in FIG. 1, the balloon catheter 1 can be embodied as 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 a guidewire insertion passage from the guidewire port 50 to the distal side of the shaft 10.

[0072] As shown in FIG. 1, the balloon catheter 1 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 inflate or deflate the balloon 2.

[0073] The shaft 10 of the balloon catheter 1 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 within the lumen of the first balloon A, as shown in Fig. 1.

[0074] Examples of materials that can be used to form the shaft 10 include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, fluorine-based resins, vinyl chloride resins, silicone resins, and natural rubber. These materials can be used alone or in combination. Among these, the material that can form the shaft 10 is preferably at least one selected from polyamide resins, polyolefin resins, and fluorine-based resins. The use of polyamide resins, polyolefin resins, or fluorine-based resins increases the slipperiness of the surface of the shaft 10, thereby improving the ease of insertion of the balloon catheter 1 into a blood vessel.

[0075] 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.

[0076] In the case of a rapid exchange balloon catheter such as that shown in FIG. 1 , a coating is preferably applied to the outer wall of the proximal shaft 16 and / or the distal shaft 15, and more preferably to both the proximal shaft 16 and the distal shaft 15. The coating can be a hydrophilic or 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 coating the outer wall of the shaft 10 with a hydrophilic or hydrophobic coating agent. The coating agent may contain a drug or additive.

[0077] Examples of hydrophilic coating agents include hydrophilic polymers such as polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, and methyl vinyl ether-maleic anhydride copolymer, or hydrophilic coating agents made from any combination thereof. 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.

[0078] Although not shown, the balloon catheter 1 may be a so-called over-the-wire balloon catheter having a guidewire passage extending from the distal to the proximal side of the shaft. In the case of an over-the-wire balloon catheter, the inflation lumen and the guidewire lumen extend to the hub 5 located at the proximal side, and the proximal openings of each lumen are preferably provided in the bifurcated hub 5. In the case of an over-the-wire balloon catheter, it is preferable that the outer wall of the outer shaft is coated. For details about the material and coating constituting the shaft, please refer to the description of the rapid exchange balloon catheter.

[0079] 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 materials may be used alone or in combination of two or more. Among these, 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.

[0080] The materials constituting the first balloon A and the second balloon are preferably elastomer resins in terms of thin film thickness and flexibility. For example, among polyamide resins, nylon 12, nylon 11, etc. are suitable as the materials constituting the first balloon A and the second balloon. Nylon 12 is more suitable because it can be relatively easily molded during blow molding. Furthermore, polyamide elastomers such as polyether ester amide elastomers and polyamide ether elastomers are preferred in terms of thin film thickness and flexibility of the first balloon A and the second balloon. Among these, polyether ester amide elastomers are preferred in terms of high yield strength and good dimensional stability of the first balloon A and the second balloon.

[0081] The materials constituting the first balloon A and the second balloon may be the same, but are preferably different. In the case of the first balloon catheter and the second balloon catheter, 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. In the case of the third balloon catheter, it is preferable to select a material such that the pressure resistance value P1 of the first balloon A is greater than the pressure resistance value P2 of the second balloon. The materials constituting the multiple second balloons may be different, but are preferably the same. By using the same material, the degree of expansion, hardness, etc. of each second balloon can be made similar.

[0082] The shaft 10 disposed inside the first balloon A may have a radiopaque marker 70 disposed at 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, or may be disposed at a position corresponding to the center of the straight tube portion 23 of the first balloon A. The shape of the radiopaque marker 70 is preferably tubular, and examples include a cylindrical shape, a polygonal cylindrical shape, a C-shaped cross-section with a notch in the tube, and a coil shape formed by winding a wire. The radiopaque marker 70 can be formed from a radiopaque substance such as lead, barium, iodine, tungsten, gold, platinum, iridium, stainless steel, titanium, or a cobalt-chromium alloy.

[0083] A tip member 60 is preferably provided at the distal end of the balloon catheter 1. 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.

[0084] The balloon catheter 1 can be used, for example, to dilate blood vessels, and is particularly suitable for dilating the aortic valve, deforming a biological valve placed in the heart, or destroying the biological valve. By using the balloon catheter 1 to deform or destroy a biological valve placed in the heart, a larger biological valve can be implanted, and the pressure gradient across the biological valve can be improved.

[0085] Next, a method for inflating the balloon 2 of the balloon catheter 1 (particularly the first balloon catheter) will be described.

[0086] The balloon catheter 1 comprises 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 composed of a plurality of second balloons arranged side by side in the circumferential direction z around the outer periphery of the first balloon A. 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. In the following cases, (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 Da of the first balloon A; (b) the second balloons constituting the balloon group B have two or more different maximum outer diameters; or (c) 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 different from the maximum outer diameter Da of the first balloon A, it is preferable to inflate the first balloon A and then the balloon group B using a pressurizer. By expanding the first balloon A before the second balloon, the second balloon expands along the outer surface of the first balloon A, and therefore the second balloon expands without shifting in the radial direction y of the first balloon A.

[0087] A balloon catheter 1 (particularly a first balloon catheter) includes a shaft 10 extending from proximal to distal in the longitudinal direction x, a first balloon A disposed at the distal end 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 around the outer periphery of the first balloon A. When the first balloon A and the balloon group B are inflated, adjacent second balloons of the balloon group B are in contact with each other, and the second balloons of the balloon group B all have the same maximum outer diameter, but this maximum outer diameter is different from the maximum outer diameter Da of the first balloon A, and the second balloon of the balloon group B has a smaller maximum outer diameter than the maximum outer diameter Da of the first balloon A, it is preferable to inflate the balloon group B using a pressurizer before inflating the first balloon A. Inflating the second balloon before the first balloon A allows the second balloon to be inflated uniformly.

[0088] This application claims the benefit of priority based on Japanese Patent Application Nos. 2023-102820 filed on June 22, 2023, 2023-102821 filed on June 22, 2023, and 2023-102822 filed on June 22, 2023. The entire contents of the specifications of Japanese Patent Application Nos. 2023-102820, 2023-102821, and 2023-102822 are incorporated herein by reference.

[0089] REFERENCE SIGNS LIST 1 balloon catheter 2 balloon 5 hub 6 fluid injection section 10 shaft 15 distal shaft 16 proximal shaft 21 proximal sleeve section 22 proximal tapered section 23 straight tube section 24 distal tapered section 25 distal sleeve section 40 guidewire tube 50 guidewire port 60 distal tip member 70 radiopaque marker 90 boundary line between distal shaft and proximal shaft A first balloon B balloon group b1, b2, b11 to b14, b21 to b23 second balloon Da maximum outer diameter of first balloon Db1, Db2, Db11 to Db14, Db21 to 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 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 constituting the balloon group are in contact with each other.

2. A balloon catheter comprising: 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 consisting of a plurality of second balloons disposed in a circumferential direction around the outer periphery of the first balloon, wherein the pressure resistance value P2 of the second balloon is greater than the pressure resistance value P1 of the first balloon.

3. The balloon catheter according to claim 2, wherein the ratio (P2 / P1) of the withstand pressure value P2 to the withstand pressure value P1 is 1.2 to 16.

4. A balloon catheter comprising: 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 consisting of a plurality of second balloons disposed in a circumferential direction around the outer periphery of the first balloon, wherein the pressure resistance value P1 of the first balloon is greater than the pressure resistance value P2 of the second balloon.

5. The balloon catheter according to claim 4, wherein the ratio (P2 / P1) of the withstand pressure value P2 to the withstand pressure value P1 is 0.08 to 0.

9.

6. A balloon catheter as described in claim 2 or 4, wherein adjacent second balloons constituting the balloon group are in contact with each other when the first balloon and the balloon group are inflated.

7. A balloon catheter as described in claim 1, 2, or 4, wherein when said first balloon and said balloon group are inflated, said balloon group is in contact with the outer circumferential surface of said first balloon.

8. A balloon catheter as described in claim 1, 2, or 4, 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.

9. The balloon catheter according to claim 1, 2 or 4, wherein the second balloons constituting the balloon group have two or more different maximum outer diameters when the balloon group is inflated.

10. A balloon catheter as described in claim 9, wherein when the first balloon and the group of balloons are inflated, 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 with the smaller maximum outer diameter is sandwiched between the second balloons with the larger maximum outer diameter.

11. A balloon catheter as described in claim 1, 2, or 4, 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.

12. The balloon catheter according to claim 11, wherein the maximum outer diameter of the second balloon constituting the balloon group is smaller than the maximum outer diameter of the first balloon.

13. The balloon catheter of claim 12, 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 constituting the balloon group, the plurality of second inflation lumens communicate with a single proximal second inflation lumen proximal to the connection positions 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.

14. The balloon catheter of claim 13, wherein the sum of the cross-sectional areas of the 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.

15. The balloon catheter of claim 13, wherein the smallest cross-sectional area among 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.

16. A balloon catheter as described in claim 1, 2, or 4, wherein the shaft has a first inflation lumen and a plurality of second inflation lumens extending longitudinally of the shaft, the first inflation lumen is connected to the first balloon, and the plurality of second inflation lumens are connected to each of a plurality of second balloons that make up the balloon group.

17. The balloon catheter according to claim 16, wherein the plurality of second inflation lumens communicate with one proximal second inflation lumen proximally of the connection points with the plurality of second balloons.

18. The balloon catheter of claim 17, 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 a cross-sectional area S2 of the proximal second inflation lumen in a direction perpendicular to the longitudinal direction.

19. The balloon catheter of claim 18, wherein a 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 second inflation lumens in a direction perpendicular to the longitudinal direction.

20. The balloon catheter of claim 18, 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 cross-sectional areas of the plurality of second inflation lumens in a direction perpendicular to the longitudinal direction.

21. The balloon catheter according to claim 1, 2 or 4, which is used for expanding an aortic valve, deforming a biological valve placed in the heart, or destroying said biological valve.

22. A method for expanding a balloon in a balloon catheter as described in claim 8, wherein a pressurizer expands the first balloon and then expands the group of balloons.

23. A method for expanding a balloon in a balloon catheter according to claim 9, wherein a pressurizer expands the first balloon and then expands the group of balloons.

24. A method for expanding a balloon in a balloon catheter according to claim 11, wherein a pressurizer expands the first balloon and then expands the group of balloons.

25. A method for expanding a balloon in a balloon catheter according to claim 12, wherein a pressurizer expands the balloon group and then expands the first balloon.

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