Balloon catheter

Abstract

Provided is a balloon catheter which is leak-resistant and in which it is possible to supply a high-pressure fluid to an inflation tube.　This balloon catheter includes: a shaft; a first balloon and a plurality of second balloons, the first and second balloons being arranged in a distal part of the shaft; and a first inflation tube and a plurality of second inflation tubes, the first and second inflation tubes being arranged in a lumen of the shaft. The lumen of the first inflation tube communicates with the lumen of the shaft and the lumen of the first balloon, and the lumens of the plurality of second inflation tubes communicate with the lumen of the shaft and the lumens of the second balloons. The shaft has: a first section, on the proximal side, in which the first inflation tube and the plurality of second inflation tubes are arranged; and a second section which is on the distal side of the first section and in which the first inflation tube and the plurality of second inflation tubes are arranged. In the first section, the shaft and the second inflation tubes are fixed to each other, and in the second section, the shaft and the second inflation tubes are not fixed to each other.

Description

Balloon catheter

[0001] The present disclosure relates to a balloon catheter.

[0002] When a stenosis hardened by calcification or the like is formed on the inner wall of a blood vessel, diseases such as angina pectoris and myocardial infarction are caused. As one of the treatment methods for these, there is an angioplasty for expanding the stenosis using a balloon catheter. Angioplasty is sometimes called percutaneous transluminal angioplasty (PTA) or percutaneous transluminal coronary angioplasty (PTCA). Angioplasty is a minimally invasive treatment that does not require an open-chest operation such as bypass surgery and is widely performed.

[0003] The 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 tube communicating with the balloon through which a fluid for expanding or contracting the balloon can move. The balloon is loaded into the blood vessel in a contracted state and delivered through the blood vessel to the stenosis. After the balloon is delivered to the stenosis, the expansion and contraction of the balloon are controlled by introducing or discharging a fluid into the inflation tube using an inflator (pressure device for the balloon) connected to the inflation tube. An example of such a balloon catheter is described in Patent Document 1. In FIG. 42 of Patent Document 1, an expansion device including an inner balloon member and a plurality of outer balloon members is described, and in FIG. 43A, a state in which the outer balloon member is expanded is described.

[0004] U.S. Patent Application Publication No. 2012 / 0209375

[0005] Patent Document 1 describes a balloon catheter comprising an inner balloon member and multiple outer balloon members, and states that inflation lumens corresponding to the inner balloon member and the multiple outer balloon members are provided in order to inflate the inner balloon member and the multiple outer balloon members at different timings. In the region where the inflation lumen corresponding to the inner balloon member and the multiple inflation lumens corresponding to each of the multiple outer balloon members are concentrated, the fluid flowing into the inflation lumen sometimes leaked out. Therefore, it was difficult to supply high-pressure fluid into the inflation lumen to prevent leakage. In addition, the rigidity in the region where multiple inflation lumens are arranged is higher than the rigidity in the region where multiple inflation lumens are not arranged, and the difference in rigidity in the longitudinal direction becomes large. For example, when a balloon catheter is inserted into a bend in a blood vessel, a kink occurs between the section where multiple inflation lumens are arranged and the section where multiple inflation lumens are not arranged.

[0006] The problem to be solved by this disclosure is to provide a balloon catheter having a first balloon, a plurality of second balloons, a first inflation tube having a lumen communicating with the lumen of the first balloon, and a plurality of second inflation tubes having lumens communicating with the lumen of the plurality of second balloons, which is less prone to leakage and can supply high-pressure fluid to the inflation tubes.

[0007] The present disclosure is as follows: [1] A balloon catheter comprising: a shaft extending longitudinally from proximal to distal; a first balloon and a plurality of second balloons disposed at the distal end of the shaft; and a first inflation tube and a plurality of second inflation tubes disposed in the lumen of the shaft, wherein the lumen of the first inflation tube communicates with the lumen of the shaft and the lumen of the first balloon, and the lumen of the plurality of second inflation tubes communicates with the lumen of the shaft and the lumen of the second balloon, wherein the shaft comprises a first proximal section in which the first inflation tube and the plurality of second inflation tubes are disposed, and a second section distal to the first section in which the first inflation tube and the plurality of second inflation tubes are disposed, wherein in the first section the shaft and the second inflation tubes are fixed to each other, and in the second section the shaft and the second inflation tubes are not fixed to each other. [2] The balloon catheter according to [1], wherein the first inflation tube and the second inflation tube are fixed to each other in the second section. [3] The balloon catheter according to [1] or [2], wherein a guidewire tube through which a guidewire is inserted is further disposed in the lumen of the shaft, and a portion of the guidewire tube is disposed in the lumen of the first balloon. [4] The balloon catheter according to any one of [1] to [3], wherein a plurality of the second balloons are arranged in the circumferential direction on the outer circumference of the first balloon. [5] The balloon catheter according to any one of [1] to [4], wherein the ratio (W2 / W1) of the length of the second section in the longitudinal direction to the length W1 of the first section in the longitudinal direction is 10 or less. [6] The balloon catheter according to any one of [1] to [5], wherein the shaft has a third section located proximal to the first section and through which the first inflation tube and a plurality of the second inflation tubes are disposed, and in the third section the shaft, the first inflation tube, and the second inflation tubes are not fixed to each other.[7] The balloon catheter according to [6], wherein the length W3 of the third section in the longitudinal direction is longer than the length W1 of the first section in the longitudinal direction. [8] The balloon catheter according to [7], wherein the ratio (W3 / W1) of the length of the third section in the longitudinal direction to the length W1 of the first section in the longitudinal direction is 1.1 to 2. [9] The balloon catheter according to any one of [6] to [8], wherein a hole is provided in the side wall of the first inflation tube in the third section to connect the lumen of the first inflation tube with the lumen of the shaft, or holes are provided in the side walls of a plurality of the second inflation tubes in the third section to connect the lumen of the second inflation tubes with the lumen of the shaft.

[0008] The balloon catheter of this disclosure has a section in the lumen of the shaft in which a first inflation tube and a plurality of second inflation tubes are arranged. This section has a section in which the shaft and the second inflation tubes are fixed to each other, and a section distal to this fixed section in which the shaft and the second inflation tubes are not fixed to each other. The presence of a section in which the shaft and the second inflation tubes are not fixed to each other makes it difficult for the fluid supplied to the lumen of the second inflation tubes to leak out of the second inflation tubes.

[0009] Figure 1 is a side view (partially a fluoroscopic view) of a balloon catheter. Figure 2 is a longitudinal cross-sectional view of the balloon catheter. Figure 3 is a longitudinal cross-sectional view of another balloon catheter. Figure 4 is a longitudinal cross-sectional view of another balloon catheter. Figure 5 is a longitudinal cross-sectional view of another balloon catheter. Figure 6 is a side view (partially a fluoroscopic view) of the balloon of the balloon catheter. Figure 7 is a cross-sectional view along line VII-VII of the balloon shown in Figure 6. Figure 8 is a cross-sectional view of a balloon different from the balloon shown in Figure 6. Figure 9 is a cross-sectional view of a balloon different from the balloon shown in Figure 6.

[0010] The embodiment of the balloon catheter according to this disclosure comprises a shaft extending longitudinally from proximal to distal, a first balloon and a plurality of second balloons disposed at the distal end of the shaft, and a first inflation tube and a plurality of second inflation tubes disposed in the lumen of the shaft, wherein the lumen of the first inflation tube communicates with the lumen of the shaft and the lumen of the first balloon, and the lumen of the plurality of second inflation tubes communicates with the lumen of the shaft and the lumen of the second balloon, and the shaft comprises a first section on the proximal side where the first inflation tube and the plurality of second inflation tubes are disposed, and a second section located distal to the first section where the first inflation tube and the plurality of second inflation tubes are disposed, wherein in the first section the shaft and the second inflation tubes are fixed to each other, and in the second section the shaft and the second inflation tubes are not fixed to each other.

[0011] When the inventors investigated the leakage of fluid in a balloon catheter having multiple inflation tubes, they found that when the shaft and inflation tubes are fixed by heat welding, heat is applied not only to the section of the shaft where the inflation tubes are located, but also to the inflation tubes not covered by the shaft. This causes the wall thickness of the inflation tubes to thin in some areas, and when high-pressure fluid is supplied to the inside of these inflation tubes, the inflation tubes cannot withstand the internal pressure, resulting in leakage. On the other hand, according to the embodiment of the balloon catheter according to the present disclosure, a second section is provided distal to the first section where the shaft and the second inflation tube are fixed to each other, and the shaft and the second inflation tube are not fixed to each other. In this second section, a gap exists between the inner wall surface of the shaft and the outer wall surface of the second inflation tube. Furthermore, since the wall thickness of the second inflation tube is kept constant, leakage can be prevented.

[0012] The balloon catheter according to the embodiments of this disclosure will be described in detail below with reference to the drawings. However, the contents of this disclosure are not limited to the illustrated examples, and modifications can be made to the extent that they are consistent with the spirit described above and below, and all such modifications are included within the technical scope of this disclosure. In each drawing, hatching and reference numerals may be omitted for convenience, in which case refer to the specification or other drawings. Also, the dimensions of various parts in the drawings may differ from the actual dimensions, as priority is given to helping to understand the features of this disclosure.

[0013] Figure 1 is a side view (partially a fluoroscopic view) of the balloon catheter. Figure 2 is a longitudinal cross-sectional view of the balloon catheter, showing an enlarged view of the connection point between the shaft 10 (particularly the distal shaft 15) and the balloon 2. 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). The same applies to Figures 3 to 6 below.

[0014] As shown in Figure 1, the balloon catheter 1 has a shaft 10 extending longitudinally from the proximal to the distal end, and a first balloon A and a plurality of second balloons B arranged at the distal end of the shaft 10. In this specification, the plurality of second balloons B may be referred to as a "balloon group". In this specification, the first balloon A and the plurality of second balloons B may be collectively referred to as "balloon 2". The number of first balloons A is one, and the number of second balloons B may be two or more. As shown in Figure 1, the plurality of second balloons B may be arranged in a circumferential direction on the outer circumference of the first balloon A.

[0015] 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 to the proximal side, i.e., toward the person being treated, is referred to as the distal side. Other members and parts 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, in this specification, all members and parts are described as having the same longitudinal direction x, radial direction y, and circumferential direction z as the shaft 10.

[0016] The first balloon A and the multiple second balloons B are connected to an inflation tube located distal to the distal end of the shaft 10. The first balloon A and the multiple second balloons B can be expanded by introducing fluid through the lumen of the shaft 10, and the first balloon A and the multiple second balloons B can be deflated by releasing the introduced fluid. To control the expansion and contraction of the first balloon A and the multiple second balloons B, an indeflerator (balloon pressurizer) may be used to introduce or release fluid. The fluid may be, for example, a mixture of contrast agent and physiological saline. The fluid may also be a pressurized fluid pressurized by a pump or the like.

[0017] As shown in Figure 2, the balloon catheter 1 has a first inflation tube 31 and a plurality of second inflation tubes 32b1 and 32b2 arranged in the lumen of the shaft 10. Hereinafter, the second inflation tubes 32b1 and 32b2 may be collectively referred to as the second inflation tube 32. The number of first inflation tubes 31 may be the same as the number of first balloons A, and the number of second inflation tubes 32 may be the same as the number of second balloons B. Figure 2 illustrates a state in which one first inflation tube 31 and two second inflation tubes 32b1 and 32b2 are arranged in the lumen of the shaft 10. The first inflation tube 31 has a lumen L31, the second inflation tube 32b1 has a lumen L32b1, and the second inflation tube 32b2 has a lumen L32b2. Hereafter, the lumen L32b1 of the second inflation tube 32b1 and the lumen L32b2 of 32b2 will be collectively referred to as the lumen L32 of the second inflation tube 32.

[0018] The balloon catheter 1 may have a guidewire tube further arranged in the lumen of the shaft 10 through which a guidewire is inserted. When the guidewire tube is arranged in the lumen of the shaft 10, the guidewire tube 40 may be arranged in the lumen L31 of the first inflation tube 31, which is arranged in the lumen L10 of the shaft 10, as shown in Figure 2. The guidewire tube 40 extends in the longitudinal direction x and has a guidewire lumen L40. A part of the guidewire tube 40 may be arranged in the lumen of the first balloon A. Figure 2 shows an example of a coaxial structure in which the guidewire tube 40 is arranged in the lumen L31 of the first inflation tube 31, but a biaxial structure in which the guidewire tube 40 and the first inflation tube 31 run parallel in the lumen L10 of the shaft 10 is also possible.

[0019] The lumen L31 of the first inflation tube 31 is in communication with the lumen L10 of the shaft 10 and the lumen of the first balloon A (not shown). The lumen L32 (L32b1, L32b2) of the second inflation tube 32 (32b1, 32b2) is in communication with the lumen L10 of the shaft 10 and the lumen of the second balloon B (not shown). The first inflation tube 31 and the first balloon A may be indirectly connected, for example, via another tube, but it is preferable that they be directly connected. The second inflation tubes 32 (32b1, 32b2) may each be indirectly connected to the second balloon B (not shown), for example, via another tube, but it is preferable that they be directly connected.

[0020] The shaft 10 has a first section on the proximal side where the first inflation tube 31 and a plurality of second inflation tubes 32 are arranged, and a second section located distal to the first section, where the first inflation tube 31 and a plurality of second inflation tubes 32 are also arranged. In the first section, the shaft 10 and the second inflation tubes 32 are fixed to each other, while in the second section, the shaft 10 and the second inflation tubes 32 are not fixed to each other. By arranging the second section, where the shaft 10 and the second inflation tubes 32 are not fixed to each other, distal to the first section where the shaft 10 and the second inflation tubes 32 are fixed to each other, a gap can be created between the inner wall surface of the shaft and the outer wall surface of the second inflation tubes 32 in the second section. In addition, since the wall thickness of the second inflation tubes 32 is kept constant, leakage can be prevented. As shown in Figure 2, the second section may be located at the distal end of the shaft 10.

[0021] In the second section, the first inflation tube 31 and the second inflation tube 32 may be fixed to each other. Of the multiple second inflation tubes 32, all of the second inflation tubes 32 may be fixed to the first inflation tube 31, or some of the second inflation tubes 32 may be fixed to the first inflation tube 31.

[0022] As shown in Figure 2, in the first section, the shaft 10 and the second inflation tube 31 are fixed to each other, and the first inflation tube 31 and the second inflation tube 32 are also fixed to each other.

[0023] The length W1 of the first section in the longitudinal direction x is preferably, for example, 8 to 20 mm, more preferably 9 mm or more, even more preferably 10 mm or more, more preferably 19 mm or less, and even more preferably 18 mm or less. That is, the length W1 of the first section in the longitudinal direction x may be 8 to 20 mm, 9 to 19 mm, or 10 to 18 mm. The length W2 of the second section in the longitudinal direction x is preferably, for example, 0.1 to 200 mm, more preferably 100 mm or less, even more preferably 10 mm or less, and particularly preferably 1 mm or less. That is, the length W2 of the second section in the longitudinal direction x may be 0.1 to 200 mm, 0.1 to 100 mm, 0.1 to 10 mm, or 0.1 to 1 mm.

[0024] The ratio (W2 / W1) of the length of the second section in the longitudinal direction x to the length of the first section in the longitudinal direction x to the length W1 may be, for example, 10 or less. Satisfying this range for the ratio (W2 / W1) further reduces the likelihood of leakage. The value of the ratio (W2 / W1) is preferably 5 or less, more preferably 1 or less, and even more preferably 0.5 or less. The lower limit of the value of the ratio (W2 / W1) is, for example, 0.01. That is, the value of the ratio (W2 / W1) may be 0.01 to 10, 0.01 to 5, 0.01 to 1, or 0.01 to 0.5.

[0025] Figure 3 is a longitudinal cross-sectional view of another balloon catheter, showing an enlarged view of the connection point between the shaft 10 (particularly the distal shaft 15) and the balloon 2. As shown in Figure 3, the shaft 10 may have a third section located proximal to the first section and in which a first inflation tube 31 and a plurality of second inflation tubes 32 are arranged. In the third section, the shaft 10, the first inflation tube 31, and the second inflation tubes 32 may not be fixed to each other. Because the shaft 10, the first inflation tube 31, and the second inflation tubes 32 are not fixed to each other, the rigidity of the third section is less than that of the first section. Therefore, by positioning the third section proximal to the first section, the difference in rigidity can be reduced, and kinking is less likely to occur even when the balloon catheter 1 is inserted into a bend in the blood vessel. In other words, by placing a third section on the shaft 10, the third section acts as a cushion regardless of the direction of bending force applied to the shaft 10 in the radial direction y, thereby preventing the occurrence of kinking. Furthermore, when a tensile force is applied to the shaft 10 having the third section, and the first and third sections are pulled, the portion of the first section near the third section is more likely to stretch. Even in this case, since the shaft 10, the first inflation tube 31, and the second inflation tube 32 are not fixed to each other in the third section, the first inflation tube 31 and the second inflation tube 32 do not stretch. As a result, it is possible to prevent the lumens of the first inflation tube 31 and the second inflation tube 32 from collapsing. Furthermore, if, for example, a guide wire tube 40 is placed in the lumen L10 of the shaft 10, even if the guide wire inserted inside the guide wire tube 40 comes into contact with a stenotic area or the like, and force from the operator is concentrated in one place, causing the guide wire to be pressed from the inside to the outside of the guide wire tube 40, the presence of the third section acts as a cushion, preventing the guide wire tube 40 from kinking.

[0026] The length W3 of the third section in the longitudinal direction x is preferably 15 to 25 mm, more preferably 16 mm or more, even more preferably 17 mm or more, more preferably 24 mm or less, and even more preferably 23 mm or less. That is, the length W3 of the third section in the longitudinal direction x may be 15 to 25 mm, 16 to 24 mm, or 17 to 23 mm.

[0027] The length W3 of the third section in the longitudinal direction x may be shorter than the length W1 of the first section in the longitudinal direction x (W3 < W1), or the same as the length W1 of the first section in the longitudinal direction x (W3 = W1), but it is preferable that it is longer than the length W1 of the first section in the longitudinal direction x (W3 > W1). Because the length W3 of the third section in the longitudinal direction x is longer than the length W1 of the first section, the difference in rigidity in the section in which the first inflation tube 31 and the multiple second inflation tubes 32 are arranged is reduced, making it even less likely for kinks to occur when the balloon catheter 1 is inserted into a blood vessel.

[0028] When the length W3 of the third section in the longitudinal direction x is longer than the length W1 of the first section in the longitudinal direction x (W3 > W1), the ratio (W3 / W1) of the length of the third section W3 in the longitudinal direction x to the length W1 of the first section in the longitudinal direction x is preferably 1.1 to 2. Satisfying this range for the ratio (W3 / W1) reduces the difference in rigidity, making kinking less likely when the balloon catheter 1 is inserted into a blood vessel. The value of the ratio (W3 / W1) is more preferably 1.2 or higher, even more preferably 1.3 or higher, even more preferably 1.9 or lower, and even more preferably 1.8 or lower. That is, the value of the ratio (W3 / W1) may be 1.1 to 2, 1.2 to 1.9, or 1.3 to 1.8.

[0029] Figure 4 is a longitudinal cross-sectional view of another balloon catheter, showing an enlarged view of the connection point between the shaft 10 (particularly the distal shaft 15) and the balloon 2. As shown in Figure 4, holes h1 to hn that connect the lumen of the first inflation tube 31 and the lumen L10 of the shaft 10 may be arranged on the side wall of the first inflation tube 31 in the third section. n represents a positive integer. Of the holes h1 to hn, hole h1 is the hole located on the nearest side in the longitudinal direction x, and hole hn is the hole located on the most distal side in the longitudinal direction x. As shown in Figure 4, if holes h1 to hn that connect the lumen of the first inflation tube 31 and the lumen L10 of the shaft 10 are arranged in the side wall of the first inflation tube 31 in the third section, the first inflation tube 31 may be fixed to the shaft 10 at a position proximal to the nearest hole h1, which is located on the nearest side in the longitudinal x direction among the holes arranged in the side wall of the first inflation tube 31. By introducing fluid into the first inflation tube 31, the fluid is introduced into the lumen of the first balloon A through the lumen L31 of the first inflation tube 31. At this time, a portion of the fluid flows out into the lumen L10 of the shaft 10 through the holes h1 to hn arranged in the side wall of the first inflation tube 31. The outflowing fluid accumulates in the lumen L10 of the shaft 10, and the accumulated fluid is introduced into the second balloon B through the lumen L32 (L32b1, L32b2) of the second inflation tube 32 (32b1, 32b2). By introducing fluid into the first inflation tube 31 in this way, the order in which the first balloon A and the second balloon B expand can be controlled. As a result, when positioning and expanding the first balloon A and the second balloon B at the affected area, there is a time lag between the expansion of the first balloon A and the expansion of the second balloon B, allowing for fine adjustment of the positions of the first balloon A and the second balloon B, making it easier to position the balloon 2. Furthermore, because the second balloon B expands later than the first balloon A, the blood perfusion flow rate can be maintained even while fine adjustments are being made to the positions of the first balloon A and the second balloon B.

[0030] The distance in the longitudinal direction x between the nearest position of hole h1, which is located on the nearest side in the longitudinal direction x among the holes arranged in the side wall of the first inflation tube 31, and the proximal end of the second inflation tube 32 may be, for example, 50 mm or less, 40 mm or less, or 30 mm or less. The position of hole hn, which is located on the most distal side in the longitudinal direction x among the holes arranged in the side wall of the first inflation tube 31, may be distal to the proximal end of the second inflation tube 32 with respect to the longitudinal direction x, as shown in Figure 4, but may also be at the same position as the proximal end of the second inflation tube 32, or may be proximal to the proximal end of the second inflation tube 32.

[0031] The shaft 10 may extend to the proximal end so as to cover the outside of the first inflation tube 31, or only the first inflation tube 31 may extend to the proximal end, with the inner surface of the proximal end of the shaft 10 fixed to the outer surface of the first inflation tube 31 and the shaft 10 positioned only distal to the fixing position between the first inflation tube 31 and the shaft 10, or only the shaft 10 may extend to the proximal end, with the outer surface of the proximal end of the first inflation tube 31 fixed to the inner surface of the shaft 10 and the first inflation tube 31 positioned only distal to the fixing position between the first inflation tube 31 and the shaft 10. By making either the first inflation tube 31 or the shaft 10 the member that extends to the proximal end, the outer diameter of the balloon catheter 1 can be reduced, thereby increasing minimal invasiveness. The first inflation tube 31 and the shaft 10 may be fixed together, for example, using an adhesive or by heat welding, but it is preferable that they be fixed together by heat welding.

[0032] If the second inflation tubes 32 (32b1, 32b2) are arranged in the lumen L10 of the shaft 10, the number of second inflation tubes 32 (32b1, 32b2) should be set according to the number of second balloons B.

[0033] Figure 5 is a longitudinal cross-sectional view of another balloon catheter, showing an enlarged cross-sectional view of the connection position between the shaft 10 (particularly the distal shaft 15) and the balloon 2. When multiple second inflation tubes 32 are present in the lumen L10 of the shaft 10, as described above, holes connecting the lumen L31 of the first inflation tube 31 and the lumen L10 of the shaft 10 may be arranged in the side wall of the first inflation tube 31 in the third section. However, as shown in Figure 5, holes connecting the lumen L32 of the second inflation tubes 32 and the lumen L10 of the shaft 10 may be arranged in the side walls of multiple second inflation tubes 32 in the third section. If a hole is provided in the side wall of the second inflation tube 32 in the third section that connects the lumen L32 of the second inflation tube 32 with the lumen L10 of the shaft 10, it is preferable that the second inflation tube 32 is fixed to the shaft 10 at a position proximal to the nearest hole h1 located on the nearest side in the longitudinal x direction among the holes provided in the side wall of the second inflation tube 32. By introducing fluid into the second inflation tube 32 (32b1, 32b2), the fluid is introduced into the lumen of the second balloon B through the lumen L32 (L32b1, L32b2) of the second inflation tube 32 (32b1, 32b2). At this time, a portion of the fluid flows out into the lumen L10 of the shaft 10 through holes h1 to hn provided in the side wall of the second inflation tube 32 (32b1, 32b2). The outflowing fluid accumulates in the lumen L10 of the shaft 10, and the accumulated fluid is introduced into the first balloon A through the lumen L31 of the first inflation tube 31. By introducing fluid into the second inflation tube 32 in this way, the order in which the first balloon A and the second balloon B expand can be controlled. As a result, the first balloon A expands later than the second balloon B, causing the first balloon A to push the multiple second balloons B that are already expanding in the radial direction y, thereby increasing the adhesion between the second balloons B and the inner wall of the blood vessel.

[0034] The distance in the longitudinal direction x between the nearest position of hole h1, which is located on the nearest side in the longitudinal direction x among the holes arranged in the side wall of the second inflation tube 32, and the proximal end of the first inflation tube 31 may be, for example, 50 mm or less, 40 mm or less, or 30 mm or less. The position of hole hn, which is located on the most distal side in the longitudinal direction x among the holes arranged in the side wall of the second inflation tube 32, may be distal to the proximal end of the first inflation tube 31 with respect to the longitudinal direction x, as shown in Figure 5, but may also be at the same position as the proximal end of the first inflation tube 31, or may be proximal to the proximal end of the first inflation tube 31.

[0035] The shaft 10 may extend to the proximal end so as to cover the outside of the second inflation tube 32, or only the second inflation tube 32 may extend to the proximal end, with the inner surface of the proximal end of the shaft 10 fixed to the outer surface of the second inflation tube 32, and the shaft 10 positioned only distal to the fixing position between the second inflation tube 32 and the shaft 10; or only the shaft 10 may extend to the proximal end, with the outer surface of the proximal end of the second inflation tube 32 fixed to the inner surface of the shaft 10, and the second inflation tube 32 positioned only distal to the fixing position between the second inflation tube 32 and the shaft 10. By making either the second inflation tube 32 or the shaft 10 the member that extends to the proximal end, the outer diameter of the balloon catheter 1 can be reduced, thereby increasing minimal invasiveness. The second inflation tube 32 and the shaft 10 may be fixed together, for example, using an adhesive, or by heat welding, but it is preferable that they be fixed together by heat welding.

[0036] If holes connecting the lumen L32 of the second inflation tube 32 and the lumen L10 of the shaft 10 are arranged on the side walls of multiple second inflation tubes 32 in the third section, the holes may be formed in each of the multiple second inflation tubes 32 (32b1, 32b2) as shown in Figure 5, or they may be formed in only one of the multiple second inflation tubes 32.

[0037] The number of holes arranged in the side wall of the first inflation tube 31 or the second inflation tube 32 may be one or more, and the number of holes may be appropriately set based on, for example, the time difference in which the first balloon A and the second balloon B are inflated. The number of holes is preferably five or more, more preferably ten or more. The upper limit of the number of holes is preferably 40 or less, more preferably 35 or less, and even more preferably 30 or less. That is, the number of holes may be 1 to 40, 5 to 35, or 10 to 30.

[0038] The holes in the side wall of the first inflation tube 31 or the second inflation tube 32 are preferably positioned so that the fluid introduced into the first inflation tube 31 or the second inflation tube 32 is discharged evenly from the inside to the outside in the radial direction y of the first inflation tube 31 or the second inflation tube 32. Specifically, the holes may be arranged in a line along the longitudinal direction x, arranged spirally with respect to the longitudinal direction x, arranged regularly, or arranged randomly. A combination of these arrangements may also be used.

[0039] The size of the holes in the side walls of the first inflation tube 31 or the second inflation tube 32 can be appropriately set based, for example, on the time difference between the inflation of the first balloon A and the second balloon B. The shape of the holes is not particularly limited, but in a side view of the first inflation tube 31 or the second inflation tube 32, the shape of the opening may be circular, elliptical, egg-shaped, or the like.

[0040] As shown in Figures 2 to 5, the balloon catheter 1 may further have a guidewire tube 40 through which a guidewire is inserted and which extends in the longitudinal direction x. As shown in Figure 4, when the guidewire tube 40 is present, it is preferable that the first inflation tube 31 and the second inflation tube 32 are arranged on the outer circumference of the guidewire tube 40. This allows the first inflation tube 31 and the second inflation tube 32 to support the guidewire tube 40, thereby preventing damage to the guidewire tube 40. As shown in Figures 2, 3, and 5, it is preferable that a portion of the guidewire tube 40 is arranged in the lumen L31 of the first inflation tube 31. Arranging a portion of the guidewire tube 40 in the lumen L31 of the first inflation tube 31 improves the operability of the balloon catheter 1. It is preferable that a portion of the guidewire tube 40 is arranged in the lumen of the first balloon A. This further prevents damage to the guidewire tube 40. The guidewire tube 40 may be arranged in a biaxial structure running parallel to the first inflation tube 31 in the lumen L10 of the shaft 10, as shown in Figure 4, or it may be arranged in a coaxial structure in the lumen L31 of the first inflation tube 31, as shown in Figures 2, 3, and 5.

[0041] Examples of materials that make up the shaft 10 include polyamide resin, polyester resin, polyurethane resin, polyolefin resin, fluororesin, vinyl chloride resin, silicone resin, natural rubber, etc. Only one of these may be used, or two or more may be used in combination. In particular, at least one of polyamide resin, polyolefin resin, and fluororesin is preferred as the material that makes up the shaft 10. By making the material that makes up the shaft 10 one of polyamide resin, polyolefin resin, or fluororesin, the slipperiness of the surface of the shaft 10 is increased, which can improve the insertion of the balloon catheter 1 into the blood vessel.

[0042] The materials constituting the first inflation tube 31, the materials constituting the second inflation tube 32, and the materials constituting the guide wire tube 40 include, for example, polyamide resins, polyester resins, polyurethane resins, polyolefin resins, fluorine resins, vinyl chloride resins, silicone resins, natural rubber, and the like. These may be used alone or in combination of two or more. Among them, at least one selected from polyamide resins, polyolefin resins, and fluorine resins is preferable for the materials constituting the first inflation tube 31, the materials constituting the second inflation tube 32, and the materials constituting the guide wire tube 40. The materials constituting the first inflation tube 31, the materials constituting the second inflation tube 32, and the materials constituting the guide wire tube 40 may be different, but are preferably the same. By using the same material, the rigidity can be made uniform.

[0043] As shown in FIG. 1, the balloon catheter 1 preferably has a plurality of second balloons B, and the plurality of second balloons B are arranged side by side in the circumferential direction z on the outer circumference of the first balloon A. The arrangement of the first balloon A and the second balloons B will be described with reference to FIGS. 6 to 9.

[0044] FIG. 6 is a side view (partial perspective view) of the balloons of the balloon catheter 1. FIG. 6 shows a state in which a balloon group composed of the first balloon A and a plurality of second balloons B is expanded. FIG. 7 is a cross-sectional view taken along line VII-VII in the balloon 2 shown in FIG. 6. The balloon catheter 1 shown in FIGS. 6 and 7 is composed of one first balloon A and six second balloons B, and the six second balloons B constitute a balloon group. In FIGS. 6 and 7, for convenience of explanation, two of the six second balloons B are denoted by reference numerals b1 and b2. When the first balloon A and the second balloons B (b1, b2) are expanded, 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.

[0045] As shown in Figures 6 and 7, the balloon catheter 1 has a balloon group consisting of multiple second balloons B arranged in the circumferential direction z around the outer circumference of the first balloon A. By expanding both the first balloon A and the balloon group, the outer diameter of the balloon 2 can be increased. As a result, the stenotic portion can be reliably expanded.

[0046] As shown in Figures 6 and 7, when the balloon catheter 1 expands the first balloon A and the balloon group, it is preferable that adjacent second balloons b1 and b2 among the multiple second balloons B constituting the balloon group 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 expansion, thereby increasing pressure resistance and thus increasing the expansion force of the balloon group. Furthermore, because adjacent second balloons b1 and b2 are in contact with each other, even if the second balloon B comes into contact with the stenosis, it is less likely to shift in the circumferential direction z of the outer circumference of the first balloon A, thus ensuring that the stenosis is reliably expanded.

[0047] When the first balloon A and the balloon group are expanded, the multiple second balloons B constituting the balloon group only need to have at least one pair of adjacent second balloons B in contact with each other, preferably two or more pairs of adjacent second balloons B in contact with each other, and more preferably all adjacent second balloons B in contact with each other. When all adjacent second balloons B are in contact with each other, the second balloons B can be expanded uniformly.

[0048] When the first balloon A and the balloon group are expanded, the second balloon B constituting the balloon group may not contact the outer peripheral surface of the first balloon A, but it is preferable that at least one of the plurality of second balloons B constituting the balloon group contacts the outer peripheral surface of the first balloon A. Since at least one of the plurality of second balloons B contacts the outer peripheral surface of the first balloon A, even if the second balloon B is pressed against the stenosis, the second balloon B contacts the outer peripheral surface of the first balloon A. Therefore, the second balloon B is less likely to shift in the radial direction y of the first balloon A, and the stenosis can be surely expanded. More preferably, all of the plurality of second balloons B constituting the balloon group contact the outer peripheral surface of the first balloon A. Since all of the plurality of second balloons B contact the outer peripheral surface of the first balloon A, the first balloon A and the second balloon B expand together with each other even if the second balloon B is pressed against the stenosis. Therefore, the pressure resistance of the balloon group can be increased.

[0049] The number of second balloons B constituting the balloon group is preferably three or more, more preferably four or more, and even more preferably five or more. By setting the lower limit of the number of second balloons B constituting the balloon group within the above range, the balloon group can more easily surround the outer circumference of the first balloon A, and the balloon group can more easily suppress the expansion of the first balloon A. As a result, when fluid is introduced into both the first balloon A and the balloon group, the first balloon A and the second balloon B suppress each other's expansion, thereby increasing the pressure resistance of balloon 2, increasing the hardness of balloon 2, and improving its expansion force. In addition, because the first balloon A and the second balloon B suppress each other's expansion, balloon 2 becomes less likely to inflate, so even if high pressure is applied to balloon 2, over-expansion of balloon 2 is suppressed, preventing balloon 2 from expanding beyond the target outer diameter, thereby reducing damage to in vivo lumens such as the aortic valve and improving safety. There is no particular upper limit to the number of second balloons B that make up the balloon group, but for example, 20 or fewer is preferred, 12 or fewer is more preferred, 10 or fewer is even more preferred, and 8 or fewer is particularly preferred. By setting the upper limit of the number of second balloons B that make up the balloon group to the above range, the second balloons B that make up the balloon group become less likely to shift in the radial y and circumferential z directions relative to the first balloon A, and the balloon group makes it easier to suppress the expansion of the first balloon A.

[0050] When the first balloon A and the balloon group are expanded, the maximum outer diameter of the circumscribed circle of balloon 2 is not particularly limited, but is preferably in the range of 5 mm to 60 mm.

[0051] The relationship between the maximum outer diameter of the first balloon A and the maximum outer diameter of the second balloon B constituting the balloon group is preferably one of the following (1) to (3): (1) When the first balloon A and the balloon group are expanded, the maximum outer diameters of all the second balloon B constituting the balloon group are the same, and the maximum outer diameter of the second balloon B is the same as the maximum outer diameter of the first balloon A. (2) When the balloon group is expanded, there are two or more types of second balloon B constituting the balloon group with different maximum outer diameters. (3) When the first balloon A and the balloon group are expanded, the maximum outer diameters of all the second balloon B constituting the balloon group are the same, and the maximum outer diameter of the second balloon B is different from the maximum outer diameter of the first balloon A. The maximum outer diameter 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 B refers to the maximum circular equivalent diameter of the second balloon B in a cross section perpendicular to the longitudinal direction x of the second balloon B.

[0052] (1) will be explained using Figure 7. As shown in Figure 7, when the first balloon A and the balloon group are expanded, the maximum outer diameter of all the second balloons B constituting the balloon group is the same, and the maximum outer diameter of the second balloons B is the same as the maximum outer diameter of the first balloon A. As a result, it is easier to balance the force that the first balloon A tries to expand with the force that the second balloons B exert by expanding to suppress the expansion of the first balloon A. As a result, the hardness of the first balloon A and the balloon group is increased, making it easier to increase the expansion force of the balloon group and allowing the constricted area to be expanded uniformly.

[0053] When the maximum outer diameter of the first balloon A and all of the second balloons B are the same, it is preferable that the maximum outer diameters of the first balloon A and the second balloons B be, for example, 3 mm to 8 mm. When the maximum outer diameters of the multiple second balloons B constituting the balloon group are all the same, it means that the maximum outer diameters of the multiple second balloons B constituting the balloon group are of similar size. Specifically, it means that the maximum outer diameter of the second balloon B with the largest maximum outer diameter among the second balloons B constituting the balloon group is between 100% and 110% of the maximum outer diameter of the second balloon B with the smallest maximum outer diameter among the second balloons B constituting the balloon group. When the maximum outer diameter of the first balloon A is the same as the maximum outer diameter of the multiple second balloons B constituting the balloon group, it means that the maximum outer diameter of the first balloon A and the maximum outer diameters of the multiple second balloons B constituting the balloon group are of similar size. Specifically, it means that the maximum outer diameter of the first balloon A is between 90% and 110% of the maximum outer diameter (for example, the average value) of the second balloons B.

[0054] (2) will be explained using Figure 8. Figure 8 is a cross-sectional view of a balloon different from the balloon shown in Figure 6, at a position corresponding to Figure 7. As shown in Figure 8, when the balloon group is expanded, because there are two or more types of second balloons B that make up the balloon group with different maximum outer diameters, multiple second balloons with different maximum outer diameters are arranged in the circumferential direction z of the outer circumference of the first balloon A. As a result, the second balloons B with the larger maximum outer diameter (b11, b12) in the balloon group come into contact with the inner wall of the blood vessel, while the second balloons B with the smaller maximum outer diameter (b13, b14) do not come into contact with the inner wall of the blood vessel. Therefore, a space is easily created between the inner wall of the blood vessel and the second balloons B (b13, b14) that do not come into contact with the inner wall of the blood vessel, allowing blood to perfuse. Furthermore, because the second balloon B (b11, b12), which has the largest outer diameter among the balloon group, comes into contact with the inner wall of the blood vessel, the number of second balloon B in contact with the inner wall of the blood vessel is limited to a portion of the balloon group. As a result, the contact points between the second balloon B and the inner wall of the blood vessel are reduced, and the stress applied from the second balloon B to the inner wall of the blood vessel can be concentrated. Consequently, the narrowed area can be reliably expanded.

[0055] As shown in Figure 8, the balloon group consists of at least three second balloons, and when the first balloon A and the balloon group are expanded, two types of second balloons B with different maximum outer diameters are arranged in the circumferential direction z around the outer circumference of the first balloon A. In such cases, it is preferable that the second balloon b13 with the smaller maximum outer diameter is sandwiched between the second balloons b11 and b12 with the larger maximum outer diameters. By sandwiching the second balloon b13 with the smaller maximum outer diameter between the second balloons b11 and b12 with the larger maximum outer diameters in the circumferential direction z around the outer circumference of the first balloon A, the space formed between the inner wall of the blood vessel and the second balloon B that is not in contact with the inner wall of the blood vessel is distributed in the circumferential direction z around the outer circumference of the first balloon A, thereby enabling stable blood perfusion.

[0056] When the balloon group is expanded, the maximum outer diameter of the multiple second balloons B constituting the balloon group may be, for example, two different sizes, three different sizes, or four or more different sizes. In particular, it is preferable that the maximum outer diameter of the second balloons B constituting the balloon group be two different sizes.

[0057] As shown in Figure 8, when the first balloon A and the balloon group are expanded, if there are two types of second balloons B constituting the balloon group with different maximum outer diameters, the ratio (Db11 / Db13) of the second balloon b11 with a larger maximum outer diameter to the maximum outer diameter Db13 of the second balloon b13 with a smaller maximum outer diameter is preferably greater than 1 and 5 or less, 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.

[0058] As shown in Figure 8, when the first balloon A and the balloon group are expanded, if there are two types of second balloons constituting the balloon group with different maximum outer diameters, the maximum outer diameter Db13 of the second balloon b13 with 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 with the larger maximum outer diameter is preferably, for example, 3.1 mm to 25 mm (particularly greater than 3.3 mm and 25 mm or less).

[0059] (3) will be explained using Figure 9. Figure 9 is a cross-sectional view of a balloon different from the balloon shown in Figure 6, at the position corresponding to Figure 7. As shown in Figure 9, when the first balloon A and the balloon group are expanded, the maximum outer diameters of the multiple second balloons B that make up the balloon group are all the same, but the maximum outer diameter of the second balloons B is different from the maximum outer diameter of the first balloon A. This makes it easier to adjust the maximum outer diameter of the balloon group by appropriately combining the first balloon A and the second balloons B which have different maximum outer diameters. The fact that the maximum outer diameters of the multiple second balloons B that make up the balloon group are all the same means that the maximum outer diameters of the multiple second balloons B that make up the balloon group are approximately the same. Specifically, it means that the maximum outer diameter of the second balloon B with the largest maximum outer diameter among the second balloons B that make up the balloon group is between 100% and 110% of the maximum outer diameter of the second balloon B with the smallest maximum outer diameter among the second balloons B that make up the balloon group.

[0060] In case (3), when the first balloon A and the balloon group are expanded, the maximum outer diameter of the multiple second balloons B constituting the balloon group may be larger than or smaller than the maximum outer diameter of the first balloon A, but it is preferable that it be smaller. By making the maximum outer diameter of the multiple second balloons B constituting the balloon group smaller than the maximum outer diameter of the first balloon A, the first balloon A can be expanded at high pressure, thereby ensuring that the constricted portion is expanded.

[0061] When the maximum outer diameter of the multiple second balloons B constituting the balloon group 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 preferably greater than 1 and 4.5 or less, more preferably 1.1 or more, even more preferably greater than 1.1, particularly preferably 1.2 or more, more preferably 4 or less, and even more preferably 3 or less.

[0062] When the maximum outer diameter of the multiple second balloons B constituting the balloon group 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 13.5 mm or less).

[0063] When the maximum outer diameter of the multiple second balloons B constituting the balloon group is smaller than the maximum outer diameter of the first balloon A, the ratio of the maximum outer diameter Db21 of the second balloon B to the maximum outer diameter Da of the first balloon A (Db21 / Da) is preferably, for example, 0.01 or more and less than 1, more preferably 0.03 or more, even more preferably 0.05 or more, even more preferably less than 0.9, even more preferably 0.2 or less, and particularly preferably 0.1 or less.

[0064] When the maximum outer diameter of the multiple second balloons B constituting the balloon group 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.

[0065] As shown in Figure 6, the first balloon A and second balloon B 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. They 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.

[0066] When the first balloon A and the balloon group are expanded, the length L1 from the distal end Ad 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 to the proximal end b1p of the second balloon b1 in the longitudinal direction x, but it is preferable that it be shorter. Because the length L1 of the first balloon A is shorter than the length L2 of the second balloon b1, the area where the first balloon A is present expands more easily than the area where the first balloon A is not present. As a result, it becomes easier to apply pressure to the area where the first balloon A is present, making it possible to apply pressure accurately to the target area. Furthermore, it is difficult to expand and apply pressure to the area where the first balloon A is not present, so it is difficult to apply load to areas other than the target area, thereby increasing the minimally invasive nature of the balloon catheter 1.

[0067] When the first balloon A and the balloon group are expanded, the length L1 from the distal end Ad of the first balloon A to the proximal end Ap 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 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, a balloon catheter 1 can be made that can accurately apply high pressure to the target site. Furthermore, when the first balloon A and the balloon group are expanded, the length L1 from the distal end Ad of the first balloon A to the proximal end Ap 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 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 with the balloon catheter 1, making it easier to expand the stenotic area or destroy the bioprosthetic valve.

[0068] As shown in Figure 1, an example of a balloon catheter 1 is a so-called rapid exchange type balloon catheter, which has a guidewire port 50 located midway from the distal to the proximal end of the shaft 10, and a guidewire insertion passage from the guidewire port 50 to the distal end of the shaft 10. As shown in Figure 1, the balloon catheter 1 may also have a hub 5 on the proximal end, and the hub 5 may be provided with a fluid injection section 6 for injecting fluid to expand or deflate the balloon 2.

[0069] In the case of a rapid exchange type balloon catheter, the shaft 10 of the balloon catheter 1 preferably has a distal shaft 15 and a proximal shaft 16 positioned proximal to the distal shaft 15. The distal shaft 15 and the proximal shaft 16 may be connected at the boundary line 90, and the distal shaft 15 and the proximal shaft 16 may be separate components. If the distal shaft 15 and the proximal shaft 16 are separate components, the proximal shaft 16 may be made of resin or metal.

[0070] In the case of a rapid exchange type balloon catheter, it is preferable that the outer walls of the proximal shaft 16 and / or distal shaft 15 are coated, and it is more preferable that both the proximal shaft 16 and the distal shaft 15 are coated. The coating can be hydrophilic or hydrophobic 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.

[0071] 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), ethylene fluoride propylene (FEP), perfluoroalkoxyalkanes (PFA), silicone oil, hydrophobic urethane resins, carbon coatings, diamond coatings, diamond-like carbon (DLC) coatings, ceramic coatings, and substances with low surface free energy terminated with alkyl groups or perfluoroalkyl groups.

[0072] Although not shown in the figures, the balloon catheter 1 may be a so-called over-the-wire type balloon catheter, having a guidewire insertion passage extending from the distal to the proximal end of the shaft. In the case of an over-the-wire type balloon catheter, it is preferable that the inflation lumen and guidewire lumen extend to a hub 5 located on the proximal end, and that the proximal opening of each lumen is provided in the bifurcated hub 5. 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 details on the materials and coatings constituting the shaft, refer to the description for rapid-exchange type balloon catheters.

[0073] Examples of materials constituting the first balloon A and the second balloon B include polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer; polyester resins such as polyethylene terephthalate and polyester elastomer; polyurethane resins such as polyurethane and polyurethane elastomer; polyphenylene sulfide resin; polyamide resins such as polyamide and polyamide elastomer; fluorine resin; silicone resin; natural rubber such as latex rubber; and the like. Only one of these may be used, or two or more may be used in combination. In particular, at least one of polyamide resins, polyester resins, and polyurethane resins is preferred for the materials constituting the first balloon A and the second balloon B.

[0074] For the materials constituting the first balloon A and the second balloon B, it is preferable to use elastomer resins from the viewpoint of thinness and flexibility. For example, among polyamide resins, nylon 12 and nylon 11 are suitable as materials constituting the first balloon A and the second balloon B. Nylon 12 is more preferable because it can be molded relatively easily during blow molding. Furthermore, from the viewpoint of thinness and flexibility of the first balloon A and the second balloon B, polyamide elastomers such as polyether ester amide elastomers and polyamide ether elastomers are preferably used. Among these, polyether ester amide elastomers are preferably used because they have high yield strength and provide good dimensional stability for the first balloon A and the second balloon B.

[0075] The materials constituting the first balloon A and the second balloon B may be the same, but it is preferable that they be different, and it is preferable to select the materials such that the pressure resistance value P2 of the second balloon B is greater than the pressure resistance value P1 of the first balloon A. The materials constituting multiple second balloons B may each be different, but it is preferable that they be the same. By being the same, the degree of expansion, hardness, etc. of each second balloon B can be made to be of a similar degree.

[0076] An X-ray opaque marker 70 may be positioned on the shaft 10 located inside the first balloon A, 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 X-ray opaque marker 70 may be positioned at a location corresponding to the center of the straight tube portion 23 of the first balloon A, or preferably at locations corresponding to both ends of the straight tube portion 23 of the first balloon A. The shape of the X-ray opaque marker 70 can be cylindrical, tubular, polygonal, C-shaped with a cut in the tube, or a coil shape made by winding a wire, with a cylindrical shape being preferred. The material constituting the X-ray opaque marker 70 can be, for example, X-ray opaque materials such as lead, barium, iodine, tungsten, gold, platinum, iridium, stainless steel, titanium, or cobalt-chromium alloy. Only one of these may be used, or two or more may be used in combination.

[0077] It is preferable that a tip member 60 is 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 by being connected to the distal end of the first balloon A as a separate member from the shaft 10, 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.

[0078] The balloon catheter 1 can be used, for example, to dilate blood vessels. The balloon catheter 1 can also be used, for example, to dilate the aortic valve, deform a bioprosthetic valve implanted in the heart, or destroy the bioprosthetic valve. Vascular stenosis can occur, for example, in the aortic valve. When stenosis occurs in the aortic valve, the aortic valve is removed and a new bioprosthetic valve is implanted. However, implanted bioprosthetic valves deteriorate over time and need to be replaced every 5 to 10 years. When a new bioprosthetic valve (artificial valve) is implanted transcatheterally due to deterioration of a surgically implanted bioprosthetic valve (artificial valve), the valve orifice area may become smaller. Therefore, the size of the new bioprosthetic valve must be smaller than the deteriorated bioprosthetic valve, leading to decreased blood flow, a pressure difference before and after the bioprosthetic valve, and a strain on the heart. Therefore, by using the balloon catheter 1 to deform or destroy a bioprosthetic valve implanted in the heart, a larger bioprosthetic valve can be implanted, improving the pressure difference before and after the bioprosthetic valve.

[0079] The method for manufacturing the balloon catheter 1 is not particularly limited. For example, the first inflation tube 31 and the second inflation tube 32, and optionally the guide wire tube 40, may be inserted into the lumen L10 of the shaft 10 and fixed using an adhesive or by heat welding. In this case, a second section is formed distal to the first section where the shaft 10 and the second inflation tube 32 are fixed to each other, in which the shaft 10 and the second inflation tube 32 are not fixed to each other. A third section may also be formed proximal to the first section, in which the shaft 10, the first inflation tube 31, and the second inflation tube 32 are not fixed to each other. To fix the first section by heat welding and to form the second and / or third sections, heat must be applied to the desired locations. For this reason, for example, an insulating material may be placed at the proximal end of the area where the second section is to be formed, or at the distal end where the third section is to be formed, to prevent the heat applied to the first section from being transferred to the second and / or third sections.

[0080] This application claims the benefit of priority based on Japanese Patent Application No. 2024-229280, filed on 25 December 2024. The entire contents of the specification of the above Japanese Patent Application No. 2024-229280 are incorporated herein by reference.

[0081] 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 section 24 Distal tapered section 25 Distal sleeve section 31 First inflation tube 32, 32b1, 32b2 Second inflation tube 40 Guidewire tube 50 Guidewire port 60 Tip component 70 Radiopaque marker 90 Boundary between distal shaft and proximal shaft A First balloon B Second balloon 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 h1-hn Hole L10 Lumen of the shaft L31 Lumen of the first inflation tube L32, L32b1, L32b2 Lumen of the second inflation tube L40 Guidewire lumen W1 Length of the first section in the longitudinal direction W2 Length of the second section in the longitudinal direction x Longitudinal direction x1 Fixed position y Radial direction z Circumferential direction

Claims

1. A balloon catheter comprising: a shaft extending longitudinally from proximal to distal; a first balloon and a plurality of second balloons disposed at the distal end of the shaft; a first inflation tube and a plurality of second inflation tubes disposed in the lumen of the shaft, wherein the lumen of the first inflation tube communicates with the lumen of the shaft and the lumen of the first balloon; the lumen of the plurality of second inflation tubes communicates with the lumen of the shaft and the lumen of the second balloon; the shaft having a first section proximal to which the first inflation tube and the plurality of second inflation tubes are disposed; and a second section distal to the first section in which the first inflation tube and the plurality of second inflation tubes are disposed, wherein in the first section the shaft and the second inflation tubes are fixed to each other; and in the second section the shaft and the second inflation tubes are not fixed to each other.

2. The balloon catheter according to claim 1, wherein the first inflation tube and the second inflation tube are fixed to each other in the second section.

3. The balloon catheter according to claim 1, wherein a guidewire tube through which a guidewire is inserted is further disposed in the lumen of the shaft, and a portion of the guidewire tube is disposed in the lumen of the first balloon.

4. The balloon catheter according to claim 1, wherein a plurality of the second balloons are arranged in a circumferential direction on the outer circumference of the first balloon.

5. The balloon catheter according to claim 1, wherein the ratio (W2 / W1) of the length of the second section in the longitudinal direction to the length W1 of the first section in the longitudinal direction is 10 or less.

6. The balloon catheter according to claim 1, wherein the shaft has a third section located proximal to the first section and in which the first inflation tube and a plurality of the second inflation tubes are arranged, and in the third section the shaft, the first inflation tube, and the second inflation tubes are not fixed to each other.

7. The balloon catheter according to claim 6, wherein the length W3 of the third section in the longitudinal direction is longer than the length W1 of the first section in the longitudinal direction.

8. The balloon catheter according to claim 7, wherein the ratio (W3 / W1) of the length of the third section in the longitudinal direction to the length W1 of the first section in the longitudinal direction is 1.1 to 2.

9. The balloon catheter according to claim 6, wherein a hole is provided in the side wall of the first inflation tube in the third section to connect the lumen of the first inflation tube with the lumen of the shaft, or a hole is provided in the side walls of a plurality of the second inflation tubes in the third section to connect the lumen of the second inflation tubes with the lumen of the shaft.

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