Balloon catheter

Abstract

Provided is a balloon catheter with a good force transfer rate, in which a force applied from a proximal side of a shaft is easily transmitted to a distal end of the shaft.　This balloon catheter has a shaft (10) that extends in a longitudinal direction from the proximal side to the distal side, and a plurality of balloons that are provided to a distal section of the shaft (10). The shaft (10) has, in a cross-section perpendicular to the longitudinal direction at the distal end of the shaft (10), an inner lumen (150) and a lumen group (600) that is configured from a plurality of outer lumens (160) that are to the outside of the inner lumen (150) and are arranged side by side in the circumferential direction of the inner lumen (150), and the shaft (10) has, in a cross-section perpendicular to the longitudinal direction, a section in which the distance (D20) between the center (C161) of a first outer lumen (161) and the center (C162) of a second outer lumen (162) is greater than the distance (D21) between the center (C161) of the first outer lumen (161) and the center (C163) of a third outer lumen (163).

Description

Balloon catheter

[0001] The present invention relates to a 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 treatments for these conditions is angioplasty, which uses a balloon catheter to dilate the stenotic area. Angioplasty is a minimally invasive treatment that does not require open chest surgery like bypass surgery, and is widely used.

[0003] Aortic stenosis is a condition in which the aortic valve becomes hardened due to calcification, making it difficult to open and obstructing blood flow. Treatment for aortic stenosis involves surgical open-chest surgery and catheter placement to replace the hardened aortic valve with a biological valve (artificial valve).

[0004] An implanted bioprosthetic valve deteriorates over time due to calcification, wear, and other factors. When an implanted bioprosthetic valve deteriorates, it must be replaced. One procedure under consideration for replacing a bioprosthetic valve involves applying high pressure to the implanted bioprosthetic valve using a braided balloon catheter or multiple balloon catheters, deforming or destroying it, expanding the valve lumen, and then implanting a new bioprosthetic valve inside the deformed or destroyed bioprosthetic valve using techniques such as transcatheter aortic valve replacement.

[0005] As examples of catheters capable of expanding a balloon at high pressure, which are used to expand hardened stenotic areas or place biological valves, Patent Document 1 discloses a balloon catheter having multiple balloon members, with multiple outer balloon members arranged to surround the outer surface of an inner balloon member, while Patent Document 2 discloses a device having a perfusion balloon with an internal passage and a balloon arranged in the internal passage of the perfusion balloon.

[0006] US Patent Application Publication No. 2012 / 0209375 JP 2018-536474 A

[0007] The shaft of a catheter having multiple balloons, such as the conventional catheters described in Patent Documents 1 and 2, may have multiple lumens, such as inflation lumens connected to each balloon and through which fluid supplied to the lumen of the balloon passes, and a guidewire lumen through which a guidewire is inserted, etc. When a shaft has multiple lumens, there is a problem in that when inserting a balloon catheter into a biological lumen such as a blood vessel, force applied from the handle side (proximal side) of the shaft is not sufficiently transmitted to the tip (distal end) of the shaft, making it difficult to insert the balloon catheter.

[0008] In view of the above circumstances, an object of the present invention is to provide a balloon catheter in which a force applied from the proximal side of the shaft is easily transmitted to the distal end of the shaft, and in which the force is highly transmissible.

[0009] The balloon catheter according to an embodiment of the present invention that has solved the above problems is as follows: [1] A balloon catheter comprising: a shaft extending longitudinally from a proximal side to a distal side; and a plurality of balloons disposed in a distal portion of the shaft, wherein the shaft, in a cross section perpendicular to the longitudinal direction at the distal end of the shaft, has a lumen group composed of an inner lumen and a plurality of outer lumens arranged outward of the inner lumen and aligned in a circumferential direction of the inner lumen, wherein, in the cross section perpendicular to the longitudinal direction at the distal end of the shaft, the lumen group includes a first outer lumen, a second outer lumen arranged adjacent to the first outer lumen in the circumferential direction of the inner lumen, and a third outer lumen arranged adjacent to the first outer lumen in the circumferential direction of the inner lumen and on the opposite side of the second outer lumen; [2] The balloon catheter according to [1], wherein, in a cross section perpendicular to the longitudinal direction, the shaft has a portion where the distance between the center of the first outer lumen and the center of the second outer lumen is greater than the distance between the center of the first outer lumen and the center of the third outer lumen. [3] The balloon catheter according to [1], wherein, in a cross section perpendicular to the longitudinal direction, the shaft has a portion where the distance between the center of the first outer lumen and the center of the second outer lumen is greater than the major axis of the outer lumen that constitutes the lumen group. [4] The balloon catheter according to [3], wherein the shaft has a distal region that is a distal region and a proximal region that is a region located proximal to the distal region, and, in a cross section perpendicular to the longitudinal direction in the proximal region, the distance between the center of the first outer lumen and the center of the second outer lumen is greater than the distance between the center of the first outer lumen and the center of the third outer lumen.[5] The balloon catheter according to any one of [1] to [4], wherein the shaft has a distal region that is a region on the distal side and a proximal region that is a region located proximal to the distal region, and the distance between the center of the shaft and the center of the inner lumen in a cross section perpendicular to the longitudinal direction in the proximal region is greater than the distance between the center of the shaft and the center of the inner lumen in a cross section perpendicular to the longitudinal direction in the distal region. [6] The balloon catheter according to any one of [3] to [5], wherein the shaft has an opening in the proximal region, in a region between adjacent outer lumens in the circumferential direction of the inner lumen, that connects the inner lumen to the outside of the shaft. [7] The balloon catheter according to [6], wherein the opening is located in a region between the first outer lumen and the second outer lumen in the circumferential direction of the inner lumen. [8] The balloon catheter according to any one of [3] to [7], wherein, in a cross section perpendicular to the longitudinal direction in the proximal region, the distance between the center of the shaft and the center of the inner lumen is greater than the shortest distance between the outer edge of the inner lumen and the outer edge of the shaft. [9] The balloon catheter according to any one of [3] to [8], wherein, in a cross section perpendicular to the longitudinal direction in the proximal region, the shortest distance between the center of the outer lumen constituting the lumen group and the center of the shaft is greater than the center-to-center distance between adjacent outer lumens in the circumferential direction of the inner lumen.

[10] The balloon catheter according to any one of [3] to [9], wherein, in a cross section perpendicular to the longitudinal direction in the proximal region, the shortest distance between the center of the outer lumen constituting the lumen group and the center of the shaft is greater than the shortest distance between the outer edge of the outer lumen and the outer edge of the shaft.

[11] The balloon catheter according to any one of [1] to

[10] , wherein the inner lumen is a guidewire lumen through which a guidewire is inserted, and the outer lumen constituting the lumen group is an inflation lumen through which a fluid supplied to the lumen of the balloon passes, and which communicates with each of the lumens of the balloons.

[12] The balloon catheter according to

[11] , further comprising a guidewire tube having a lumen communicating with the guidewire lumen, the guidewire tube being disposed in the lumen of the balloon.

[13] A balloon catheter according to any one of [1] to

[12] , which is used to expand an aortic valve, deform a biological valve placed in the heart, or destroy the biological valve.

[0010] According to the balloon catheter, the shaft has a portion in which the distance between the center of the first outer lumen and the center of the second outer lumen is greater than the distance between the center of the first outer lumen and the center of the third outer lumen, so that the thickness of the shaft between the first outer lumen and the second outer lumen is greater than the thickness of the shaft between the first outer lumen and the third outer lumen. As a result, the rigidity of the shaft portion between the first outer lumen and the second outer lumen is increased, and force applied from the proximal side of the shaft is more easily transmitted to the distal end of the shaft, resulting in a balloon catheter with good force transmission efficiency.

[0011] 1 shows a side view of a balloon catheter according to one embodiment of the present invention; 2 shows a side view of a balloon of the balloon catheter shown in FIG. 1; 3 shows a side view of a shaft at the distal region of the balloon catheter shown in FIG. 1; 4 shows a cross-sectional view of the shaft shown in FIG. 3 taken along line IV-IV; 5 shows a side view of a shaft at the proximal region of the balloon catheter shown in FIG. 1; and 6 shows a cross-sectional view of the shaft shown in FIG. 5 taken along line VI-VI.

[0012] The present invention will be described below based on the embodiments, but the present invention is not limited to the following embodiments and can be implemented with appropriate modifications within the scope of the above and below-described purposes, and all such modifications are included within the technical scope of the present invention. In addition, hatching and component symbols may be omitted in each drawing for convenience. In such cases, please refer to the specification or other drawings. Furthermore, the dimensions of various components in the drawings may differ from the actual dimensions, as priority is given to helping understand the features of the present invention.

[0013] A balloon catheter according to an embodiment of the present invention comprises a shaft extending longitudinally from a proximal side to a distal side and a plurality of balloons disposed in a distal portion of the shaft. In a cross section perpendicular to the longitudinal direction at the distal end of the shaft, the shaft has an inner lumen and a lumen group composed of a plurality of outer lumens arranged outward of the inner lumen and aligned in a circumferential direction of the inner lumen. In the cross section perpendicular to the longitudinal direction at the distal end of the shaft, the lumen group includes a first outer lumen, a second outer lumen arranged adjacent to the first outer lumen in the circumferential direction of the inner lumen, and a third outer lumen arranged adjacent to the first outer lumen in the circumferential direction of the inner lumen and on the opposite side of the second outer lumen. In the cross section perpendicular to the longitudinal direction at the distal end of the shaft, the shaft has a portion where the distance between the center of the first outer lumen and the center of the second outer lumen is greater than the distance between the center of the first outer lumen and the center of the third outer lumen.

[0014] Balloon catheters according to embodiments of the present invention will now be described with reference to Figures 1 to 6. Figure 1 is a side view of a balloon catheter according to an embodiment of the present invention, and Figure 2 is a side view of a balloon of the balloon catheter shown in Figure 1. Figure 3 is a side view of the shaft in the distal region of the balloon catheter shown in Figure 1. Figure 4 is a cross-sectional view of the shaft shown in Figure 3 taken along line IV-IV, which is a cross-sectional view perpendicular to the longitudinal direction of the shaft. Figure 5 is a side view of the shaft in the proximal region of the balloon catheter shown in Figure 1. Figure 6 is a cross-sectional view of the shaft shown in Figure 5 taken along line VI-VI, which is a cross-sectional view perpendicular to the longitudinal direction of the shaft.

[0015] As shown in Figures 1 and 2, the balloon catheter 1 has a shaft 10 extending longitudinally from the proximal side to the distal side, and a plurality of balloons 20 arranged in the distal portion of the shaft 10.

[0016] The shaft 10 has a longitudinal direction x1, a radial direction y1 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 x1, and a circumferential direction z1 along the outer edge of the shaft 10 in a cross section perpendicular to the longitudinal direction x1. In this specification, the direction toward the user's hand in the longitudinal direction x1 is referred to as the proximal side, and the side opposite the proximal side, i.e., the direction toward the treatment subject, is referred to as the distal side.

[0017] 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 x1, radial direction y1, and circumferential direction z1 of the shaft 10. However, for ease of understanding, this specification will be described as assuming that all members and parts have the same longitudinal, radial, and circumferential directions as the longitudinal direction x1, radial direction y1, and circumferential direction z1 of the shaft 10.

[0018] The balloon 20 is connected to the distal portion of the shaft 10. The balloon 20 can be expanded by introducing a fluid through the lumen of the shaft 10, and can be deflated by discharging the fluid. To control the expansion and contraction of the balloon 20, an indeflator (a balloon pressurizer) can be used to introduce or discharge the fluid. The fluid may be, for example, saline or a mixture of a contrast agent and saline. The fluid may also be a pressurized fluid pressurized by a pump or the like.

[0019] Examples of materials that can be used to form the balloon 20 include polyamide resins such as nylon 11 and nylon 12, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyurethane resins, and thermoplastic elastomers such as polyether block amide copolymers.

[0020] The materials constituting each of the multiple balloons 20 may be different, but are preferably the same. That is, it is preferable that each of the multiple balloons 20 is made of the same material. By using the same material constituting each of the multiple balloons 20, it is possible to make the degree of expansion and hardness of the balloons 20 approximately the same in the circumferential direction z1 of the balloons 20.

[0021] In the inflated state of the balloons 20, the maximum outer diameters of the multiple balloons 20 may be different, but are preferably the same. The same maximum outer diameter of the multiple balloons 20 means that the maximum outer diameters of the multiple balloons 20 are approximately the same, specifically, that the maximum outer diameter of one balloon 20 is 90% to 110% of the maximum outer diameters of all the other balloons 20. Having the same maximum outer diameter of the multiple balloons 20 in the inflated state of the balloons 20 makes it easier to synchronize the inflation timing of all the balloons 20 and to control the inflation of the balloons 20. The inflated state of the balloons 20 refers to a state in which a fluid is introduced into the lumen of each of the multiple balloons 20, and all of the balloons 20 are inflated.

[0022] 1 and 2 , the multiple balloons 20 preferably include a first balloon 21 and multiple second balloons 22 arranged outside the first balloon 21 and in a line in the circumferential direction of the first balloon 21. In other words, the multiple balloons 20 preferably include the first balloon 21 and multiple second balloons 22, and the multiple second balloons 22 are preferably arranged along the outer periphery of the first balloon 21.

[0023] The number of first balloons 21 may be multiple, but is preferably one. That is, the balloon catheter 1 preferably has one first balloon 21 and multiple second balloons 22. By having only one first balloon 21, the first balloon 21 is less likely to move inside the multiple second balloons 22 when the balloon 20 is in an inflated state. As a result, the first balloon 21 is more likely to suppress the inflation of the multiple second balloons 22, which increases the hardness of the balloon 2 and makes it easier to increase the inflation force.

[0024] The number of second balloons 22 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 22 within the above range, the first balloon 21 and the second balloon 22 are less likely to shift position when the balloon 20 is inflated, thereby increasing the inflation force of the balloon 20. Furthermore, the number of second balloons 22 is 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 22 within the above range, the outer diameter of the balloon 20 is less likely to become excessively large, thereby improving the minimally invasive nature of the balloon catheter 1.

[0025] When the multiple balloons 20 are in an inflated state, the lengths in the longitudinal direction x1 from the distal end 20d of each balloon 20 to the proximal end 20p of each balloon 20 may be the same or different. When the multiple balloons 20 include a first balloon 21 and multiple second balloons 22, the lengths L2 in the longitudinal direction x1 from the distal end 20d of each second balloon 22 to the proximal end 20p of each second balloon 22 may be different but are preferably the same. The lengths L2 in the longitudinal direction x1 from the distal end 20d to the proximal end 20p of each second balloon 22 being the same means that the lengths L2 in the longitudinal direction x1 of the multiple second balloons 22 are approximately the same. Specifically, this means that the length L2 in the longitudinal direction x1 of one second balloon 22 is 90% to 110% of the lengths L2 in the longitudinal direction x1 of all the other second balloons 22. Since the length L2 in the longitudinal direction x1 of each of the multiple second balloons 22 when the balloon 20 is in an expanded state is the same, it becomes easier to align the timing at which all of the second balloons 22 expand, making it easier to control the expansion of the balloon 20.

[0026] As shown in FIG. 2, the balloon 20 preferably has a straight tube section 203, a proximal tapered section 202 located proximal to the straight tube section 203, a proximal sleeve section 201 located proximal to the proximal tapered section 202, a distal tapered section 204 located distal to the straight tube section 203, and a distal sleeve section 205 located distal to the distal tapered section 204.

[0027] The straight tube portion 203 is preferably substantially cylindrical, having approximately the same diameter in the longitudinal direction x1, but may have different diameters in the longitudinal direction x1. The proximal tapered portion 202 and the distal tapered portion 204 are preferably formed into a substantially conical or truncated conical shape, with diameters decreasing as they move away from the straight tube portion 203. Having the largest diameter in the straight tube portion 203 ensures that the straight tube portion 203 of the balloon 20 can adequately contact the lesion when the balloon 20 is inflated at a lesion such as a stenosis, facilitating treatment such as dilation of the lesion. Furthermore, because the proximal tapered portion 202 and the distal tapered portion 204 are tapered, the outer diameters of the proximal and distal ends of the balloon 20 can be reduced when the balloon 20 is deflated, thereby reducing the step between the shaft 10 and the balloon 20. Therefore, the outer surface of the balloon catheter 1 is smooth when the balloon 20 is deflated, facilitating insertion of the balloon catheter 1 into a body cavity.

[0028] In balloon 20, proximal tapered section 202, straight tube section 203, and distal tapered section 204 are sections that expand when a fluid is introduced into balloon 20, whereas proximal sleeve section 201 and distal sleeve section 205 are preferably sections that do not expand. Since proximal sleeve section 201 and distal sleeve section 205 do not expand, at least a portion of proximal sleeve section 201 and at least a portion of distal sleeve section 205 can each be configured to be easily fixed to shaft 10.

[0029] In a cross section perpendicular to the longitudinal direction x1 at the distal end 10d of the shaft 10, the shaft 10 has an inner lumen 150 and a lumen group 600 consisting of a plurality of outer lumen 160 arranged outside the inner lumen 150 and in a circumferential direction z1 of the inner lumen 150.

[0030] The inner lumen 150 is a lumen disposed inside the lumen group 600 made up of multiple outer lumens 160 in a cross section perpendicular to the longitudinal direction x1 at the distal end 10d of the shaft 10. The inner lumen 150 does not have to be located inside the lumen group 600 at locations other than the distal end 10d of the shaft 10, such as the proximal end 10p of the shaft 10 or the central portion of the shaft 10 in the longitudinal direction x1; the lumen located inside the lumen group 600 at the distal end 10d of the shaft 10 is referred to as the inner lumen 150.

[0031] 1 shows a so-called rapid exchange type balloon catheter 1 having a guidewire port 50 midway from the distal side to the proximal side of the shaft 10 and a guidewire tube 40 that functions as a guidewire passage from the guidewire port 50 to the distal side of the shaft 10. The balloon catheter 1 preferably has a distal shaft 15 and a proximal shaft 16, and the distal shaft 15 and the proximal shaft 16 may be separate members, with the proximal end of the distal shaft 15 connected to the distal end of the proximal shaft 16 to form the shaft 10 that extends from the balloon 20 to the proximal end of the balloon catheter 1. Alternatively, a single shaft 10 may extend from the balloon 20 to the proximal end of the balloon catheter 1, and the distal shaft 15 and the proximal shaft 16 may each be composed of multiple tubular members.

[0032] The shaft 10 is preferably made of resin, metal, or a combination of resin and metal. Using resin as the constituent material of the shaft 10 facilitates imparting flexibility and elasticity to the shaft 10. Furthermore, using metal as the constituent material of the shaft 10 can improve the deliverability of the balloon catheter 1. Examples of resins that can be used to form the shaft 10 include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, fluorine-containing resins, vinyl chloride resins, silicone resins, natural rubber, and synthetic rubber. These may be used alone or in combination. Examples of metals that can be used to form the shaft 10 include stainless steels such as SUS304 and SUS316, platinum, nickel, cobalt, chromium, titanium, tungsten, gold, Ni-Ti alloys, Co-Cr alloys, and combinations thereof. When the shaft 10 is composed of a distal shaft 15 and a proximal shaft 16 that are separate members, the distal shaft 15 may be made of resin, and the proximal shaft 16 may be made of metal, for example. Additionally, the shaft 10 may have a laminated construction of different materials or the same materials.

[0033] The balloon 20 and the shaft 10 can be joined by bonding with an adhesive, welding, or by attaching a ring-shaped member to the overlapping portion of the end of the balloon 20 and the shaft 10 and crimping the end. Among these, it is preferable that the balloon 20 and the shaft 10 are joined by welding. By joining the balloon 20 and the shaft 10 by welding, the bond between the balloon 20 and the shaft 10 is less likely to come loose even when the balloon 20 is repeatedly expanded or contracted, and the bond strength can be improved.

[0034] 1 , a hub 5 may be provided on the proximal side of the shaft 10. The hub 5 may also be provided with a fluid injecting section 6 that communicates with a flow path for fluid supplied to the interior of the balloon 20.

[0035] The shaft 10 and the hub 5 can be joined by, for example, bonding with an adhesive, welding, etc. Among these, it is preferable that the shaft 10 and the hub 5 are joined by adhesive. By joining the shaft 10 and the hub 5 by adhesive, the bond strength between the shaft 10 and the hub 5 can be increased and the durability of the balloon catheter 1 can be improved when the shaft 10 and the hub 5 are made of different materials, for example, when the shaft 10 is made of a highly flexible material and the hub 5 is made of a highly rigid material.

[0036] The inner lumen 150 and the outer lumen 160 extend in the longitudinal direction x1. In a cross section of the shaft 10 perpendicular to the longitudinal direction x1, the cross-sectional area of ​​the inner lumen 150 is preferably larger than the cross-sectional area of ​​the outer lumen 160. Having the cross-sectional area of ​​the inner lumen 150 larger than the cross-sectional area of ​​the outer lumen 160 makes it easier to impart appropriate flexibility to the shaft 10, allowing it to bend easily along a curved lumen in a living body, thereby improving minimal invasiveness.

[0037] In a cross section perpendicular to the longitudinal direction x1 of the shaft 10, the cross-sectional area of ​​the inner lumen 150 is preferably 1.5 times or more, more preferably 2.0 times or more, and even more preferably 2.5 times or more, the cross-sectional area of ​​the outer lumen 160. By setting the lower limit of the ratio of the cross-sectional areas of the inner lumen 150 to the outer lumen 160 within the above range, the shaft 10 can be imparted with appropriate flexibility, making it possible to make the shaft 10 easily bendable along a curved intravital lumen. Furthermore, in a cross section perpendicular to the longitudinal direction x1 of the shaft 10, the cross-sectional area of ​​the inner lumen 150 is preferably 10 times or less, more preferably 9 times or less, and even more preferably 8 times or less the cross-sectional area of ​​the outer lumen 160. By setting the upper limit of the ratio of the cross-sectional areas of the inner lumen 150 to the outer lumen 160 within the above range, the outer diameter of the shaft 10 is less likely to become large, thereby improving minimal invasiveness.

[0038] In a cross section perpendicular to the longitudinal direction x1 of the shaft 10, the cross-sectional areas of the multiple outer lumens 160 constituting the lumen group 600 may be different, but are preferably the same. The cross-sectional areas of the multiple outer lumens 160 constituting the lumen group 600 being the same means that the cross-sectional areas of the multiple outer lumens 160 constituting the lumen group 600 are approximately the same, and specifically means that the cross-sectional area of ​​one outer lumen 160 is 90% to 110% of the cross-sectional areas of all the other outer lumens 160. When the cross-sectional areas of the multiple outer lumens 160 constituting the lumen group 600 are the same, the rigidity of the shaft 10 in the circumferential direction z1 becomes approximately the same, and the flexibility of the shaft 10 in the circumferential direction z1 tends to become approximately the same.

[0039] 4 , in a cross section perpendicular to the longitudinal direction x1 at the distal end 10d of the shaft 10, the lumen group 600 includes a first outer lumen 161, a second outer lumen 162 disposed adjacent to the first outer lumen 161 in the circumferential direction z1 of the inner lumen 150, and a third outer lumen 163 disposed adjacent to the first outer lumen 161 in the circumferential direction z1 of the inner lumen 150 and on the opposite side of the second outer lumen 162. In other words, the lumen group 600 includes the first outer lumen 161, the second outer lumen 162 disposed on one side of the first outer lumen 161 in the circumferential direction z1 of the inner lumen 150, and the third outer lumen 163 disposed on the other side of the first outer lumen 161 in the circumferential direction z1 of the inner lumen 150. In other words, the second outer lumen 162, the first outer lumen 161, and the third outer lumen 163 are arranged in this order toward one side in the circumferential direction z1 of the inner lumen 150.

[0040] 4 , in a cross section perpendicular to the longitudinal direction x1, the shaft 10 has a portion where the distance D20 between the center C161 of the first outer lumen 161 and the center C162 of the second outer lumen 162 is greater than the distance D21 between the center C161 of the first outer lumen 161 and the center C163 of the third outer lumen 163. The center C161 of the first outer lumen 161 in the cross section perpendicular to the longitudinal direction x1 refers to the centroid of the outer edge of the cross-sectional shape of the first outer lumen 161. Similarly, the center C162 of the second outer lumen 162 in the cross section perpendicular to the longitudinal direction x1 refers to the centroid of the outer edge of the cross-sectional shape of the second outer lumen 162, and the center C163 of the third outer lumen 163 in the cross section perpendicular to the longitudinal direction x1 refers to the centroid of the outer edge of the cross-sectional shape of the third outer lumen 163.

[0041] In a cross section perpendicular to the longitudinal direction x1, the shaft 10 has a portion in which the distance D20 between the center C161 of the first outer inner lumen 161 and the center C162 of the second outer inner lumen 162 is greater than the distance D21 between the center C161 of the first outer inner lumen 161 and the center C163 of the third outer inner lumen 163.This allows the distance between the first outer inner lumen 161 and the second outer inner lumen 162 in the circumferential direction z1 of the inner lumen 150 to be greater than the distance between the first outer inner lumen 161 and the third outer inner lumen 163 in the circumferential direction z1 of the inner lumen 150. Therefore, in the circumferential direction z1 of the inner lumen 150, the thickness of the shaft 10 in the portion between the first outer lumen 161 and the second outer lumen 162 can be made greater than the thickness of the shaft 10 in the portion between the first outer lumen 161 and the third outer lumen 163, thereby increasing the rigidity of the portion of the shaft 10 between the first outer lumen 161 and the second outer lumen 162. Because the shaft 10 has this rigid, thickened portion over a certain section in the longitudinal direction x1, force applied from the proximal side of the shaft 10 is more easily transmitted to the distal end 10d of the shaft 10, resulting in a balloon catheter 1 with good force transmission efficiency.

[0042] In a cross section perpendicular to the longitudinal direction x1, the distance D20 between the center C161 of the first outer lumen 161 and the center C162 of the second outer lumen 162 is preferably 1.5 times or more, more preferably 1.7 times or more, and even more preferably 2.0 times or more, the distance D21 between the center C161 of the first outer lumen 161 and the center C163 of the third outer lumen 163. By setting the lower limit of the ratio of the distance D20 between the center C161 of the first outer lumen 161 and the center C162 of the second outer lumen 162 to the distance D21 between the center C161 of the first outer lumen 161 and the center C163 of the third outer lumen 163 within the above range, the wall thickness of the shaft 10 in the portion between the first outer lumen 161 and the second outer lumen 162 is likely to be thick, and the rigidity of the shaft 10 is likely to be increased. Furthermore, in a cross section perpendicular to the longitudinal direction x1, the distance D20 between the center C161 of the first outer lumen 161 and the center C162 of the second outer lumen 162 is preferably 10 times or less, more preferably 7 times or less, and even more preferably 5 times or less, the distance D21 between the center C161 of the first outer lumen 161 and the center C163 of the third outer lumen 163. By setting the upper limit of the ratio of the distance D20 between the center C161 of the first outer lumen 161 and the center C162 of the second outer lumen 162 to the distance D21 between the center C161 of the first outer lumen 161 and the center C163 of the third outer lumen 163 within the above range, the outer diameter of the shaft 10 is less likely to become excessively large, thereby improving the minimally invasive nature of the balloon catheter 1.

[0043] In a cross section perpendicular to the longitudinal direction x1, the shaft 10 preferably has a portion in which the distance D20 between the center C161 of the first outer lumen 161 and the center C162 of the second outer lumen 162 is greater than the major axis of the outer lumen 160 constituting the lumen group 600. By having a portion in which the distance D20 between the center C161 of the first outer lumen 161 and the center C162 of the second outer lumen 162 is greater than the major axis of the outer lumen 160 constituting the lumen group 600, it becomes easier to greatly increase the distance between the first outer lumen 161 and the second outer lumen 162 in the circumferential direction z1 of the inner lumen 150. As a result, the wall thickness of the shaft 10 is increased in the portion between the first outer lumen 161 and the second outer lumen 162, which increases the rigidity of the shaft 10 and improves force transmissibility.

[0044] In a cross section perpendicular to the longitudinal direction x1, the distance D20 between the center C161 of the first outer lumen 161 and the center C162 of the second outer lumen 162 is preferably 1.1 times or more, more preferably 1.2 times or more, and even more preferably 1.3 times or more, the major axis of the outer lumen 160 constituting the lumen group 600. By setting the lower limit of the ratio of the distance D20 between the center C161 of the first outer lumen 161 and the center C162 of the second outer lumen 162 to the major axis of the outer lumen 160 constituting the lumen group 600 within the above range, it becomes easier to ensure a sufficient distance between the first outer lumen 161 and the second outer lumen 162 and ensure a sufficient wall thickness, thereby increasing the rigidity of the shaft 10. Furthermore, in a cross section perpendicular to the longitudinal direction x1, the distance D20 between the center C161 of the first outer lumen 161 and the center C162 of the second outer lumen 162 is preferably 5.0 times or less, more preferably 4.5 times or less, and even more preferably 4.0 times or less, the major axis of the outer lumen 160 constituting the lumen group 600. By setting the upper limit of the ratio of the distance D20 between the center C161 of the first outer lumen 161 and the center C162 of the second outer lumen 162 to the major axis of the outer lumen 160 constituting the lumen group 600 within the above range, it is possible to prevent the outer diameter of the shaft 10 from becoming excessively large, thereby achieving a minimally invasive balloon catheter 1.

[0045] As shown in Figures 1, 3 and 5, the shaft 10 preferably has a distal region A3, which is a region on the distal side, and a proximal region A4, which is a region located proximal to the distal region A3.

[0046] The distal region A3 includes the distal end 10d of the shaft 10, and is preferably at least 1 / 30 of the length in the longitudinal direction x1 from the distal end 10d of the shaft 10 to the proximal end 10p of the shaft 10, extending from the distal end 10d of the shaft 10 toward the proximal side; more preferably at least 1 / 20 of the length in the longitudinal direction x1 from the distal end 10d of the shaft 10 to the proximal end 10p of the shaft 10, extending from the distal end 10d of the shaft 10 toward the proximal side; and even more preferably at least 1 / 10 of the length in the longitudinal direction x1 from the distal end 10d of the shaft 10 to the proximal end 10p of the shaft 10, extending from the distal end 10d of the shaft 10 toward the proximal side.

[0047] The proximal region A4 is located more proximal than the distal region A3, and is preferably an area that is 1 / 50 or more of the length in the longitudinal direction x1 from the distal end 10d of the shaft 10 to the proximal end 10p of the shaft 10, more preferably an area that is 1 / 30 or more of the length in the longitudinal direction x1 from the distal end 10d of the shaft 10 to the proximal end 10p of the shaft 10, and even more preferably an area that is 1 / 20 or more of the length in the longitudinal direction x1 from the distal end 10d of the shaft 10 to the proximal end 10p of the shaft 10.

[0048] When the shaft 10 is configured to have a distal shaft 15 and a proximal shaft 16, the distal region A3 includes the distal end 15d of the distal shaft 15, and preferably is at least 1 / 30 of the length in the longitudinal direction x1 from the distal end 15d of the distal shaft 15 to the proximal end 15p of the distal shaft 15, a region extending from the distal end 15d of the distal shaft 15 toward the proximal side, more preferably is at least 1 / 20 of the length in the longitudinal direction x1 from the distal end 15d of the distal shaft 15 to the proximal end 15p of the distal shaft 15, a region extending from the distal end 15d of the distal shaft 15 toward the proximal side, and even more preferably is at least 1 / 10 of the length in the longitudinal direction x1 from the distal end 15d of the distal shaft 15 to the proximal end 15p of the distal shaft 15, a region extending from the distal end 15d of the distal shaft 15 toward the proximal side. Furthermore, the proximal region A4 is located more proximal than the distal region A3, includes the proximal end 15p of the distal shaft 15, and is preferably at least 1 / 50 of the length in the longitudinal direction x1 from the distal end 15d of the distal shaft 15 to the proximal end 15p of the distal shaft 15, a region extending from the proximal end 15p of the distal shaft 15 toward the distal side, more preferably at least 1 / 30 of the length in the longitudinal direction x1 from the distal end 15d of the distal shaft 15 to the proximal end 15p of the distal shaft 15, a region extending from the proximal end 15p of the distal shaft 15 toward the distal side, and even more preferably at least 1 / 20 of the length in the longitudinal direction x1 from the distal end 15d of the distal shaft 15 to the proximal end 15p of the distal shaft 15, a region extending from the proximal end 15p of the distal shaft 15 toward the distal side.

[0049] As shown in Figure 6, in a cross section perpendicular to the longitudinal direction x1 in the proximal region A4, it is preferable that the distance D20 between the center C161 of the first outer lumen 161 and the center C162 of the second outer lumen 162 is greater than the distance D21 between the center C161 of the first outer lumen 161 and the center C163 of the third outer lumen 163.

[0050] In a cross section perpendicular to the longitudinal direction x1 in the proximal region A4, the distance D20 between the center C161 of the first outer lumen 161 and the center C162 of the second outer lumen 162 is greater than the distance D21 between the center C161 of the first outer lumen 161 and the center C163 of the third outer lumen 163, so that the distance between the first outer lumen 161 and the second outer lumen 162 in the circumferential direction z1 of the inner lumen 150 can be greater than the distance between the first outer lumen 161 and the third outer lumen 163 in the circumferential direction z1 of the inner lumen 150. In a cross section perpendicular to the longitudinal direction x1 at the proximal region A4 located a certain distance from the tip of the shaft 10, the thickness of the portion of the shaft 10 between the first outer lumen 161 and the second outer lumen 162 in the circumferential direction z1 of the inner lumen 150 is made thicker than the thickness of the portion of the shaft 10 between the first outer lumen 161 and the third outer lumen 163, thereby increasing the rigidity of the portion of the shaft 10 between the first outer lumen 161 and the second outer lumen 162. As a result, the shaft 10 has this thickened, highly rigid portion in the proximal region A4, which makes it easier for a force applied from the proximal side of the shaft 10 to be transmitted to the distal end 10d of the shaft 10, thereby improving the force transmissibility of the balloon catheter 1, which has a high force transmissibility.

[0051] In the longitudinal direction x1, the length of the proximal region A4 is preferably equal to or shorter than the length of the distal region A3. By making the length of the proximal region A4 the same as or shorter than the length of the distal region A3, the length of the highly flexible proximal region A4 and the length of the distal region A3, which have appropriate rigidity, are balanced throughout the shaft 10, resulting in a shaft 10 with good insertability. Furthermore, in the longitudinal direction x1, the length of the proximal region A4 is more preferably shorter than the length of the distal region A3. By making the length of the proximal region A4 shorter than the length of the distal region A3, the insertability of the shaft 10 can be further improved.

[0052] 4 and 6, the distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 in a cross section perpendicular to the longitudinal direction x1 in the proximal region A4 is preferably greater than the distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 in a cross section perpendicular to the longitudinal direction x1 in the distal region A3. In Fig. 4, the position of the center C10 of the shaft 10 in a cross section perpendicular to the longitudinal direction x1 in the distal region A3 coincides with the position of the center C150 of the inner lumen 150, and the distance D22 is 0. The distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 in the proximal region A4 is greater than the distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 in the distal region A3, so that the position of the inner lumen 150 is closer to the outer periphery of the shaft 10 in the proximal region A4 than in the distal region A3. As a result, in a cross section perpendicular to the longitudinal direction x1 of the shaft 10, in a distal portion of the shaft 10 such as the distal region A3, the inner lumen 150 is located in the central portion of the shaft 10, whereas in a proximal portion of the shaft 10 such as the proximal region A4, a partition dividing the inner lumen 150 and the outer lumen 160 is present in the central portion of the shaft 10. Therefore, in the proximal portion of the shaft 10, the rigidity of the central portion of the shaft 10 in a cross section perpendicular to the longitudinal direction x1 of the shaft 10 is increased, making the shaft 10 less likely to bend and facilitating the transmission of a force applied from the proximal end 10p of the shaft 10 to the distal side. In the shaft 10 shown in Fig. 6, the inner lumen 150 is not located inside the lumen group 600 composed of multiple outer lumens 160, and there is an outer lumen 160 located more inward of the shaft 10 than the inner lumen 150. However, as shown in Fig. 4, at the distal end 10d of the shaft 10, the lumen located inside the lumen group 600 composed of multiple outer lumens 160 is referred to as the inner lumen 150.

[0053] The distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 in a cross section perpendicular to the longitudinal direction x1 preferably increases from the distal end 10d to the proximal end 10p. That is, the distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 in a cross section perpendicular to the longitudinal direction x1 preferably increases from the distal end to the proximal end of the shaft 10. Since the distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 increases from the distal end 10d to the proximal end 10p, the position of the inner lumen 150 approaches the outer periphery of the shaft 10 toward the proximal side. Therefore, the rigidity of the central portion of the shaft 10 in a cross section perpendicular to the longitudinal direction x1 of the shaft 10 increases toward the proximal side of the shaft 10, making the shaft 10 less likely to bend on the proximal side of the shaft 10. As a result, force applied from the proximal end 10p of the shaft 10 is easily transmitted to the distal end 10d of the shaft 10, resulting in a balloon catheter 1 with good force transmission properties.

[0054] The distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 in a cross section perpendicular to the longitudinal direction x1 in the proximal region A4 is preferably at least 1.1 times, more preferably at least 1.2 times, and even more preferably at least 1.3 times the distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 in a cross section perpendicular to the longitudinal direction x1 in the distal region A3. By setting the lower limit of the ratio of the distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 in the proximal region A4 to the distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 in the distal region A3 within the above range, the inner lumen 150 can be brought sufficiently closer to the outer periphery of the shaft 10 in the proximal region A4 than in the distal region A3, making it easier to increase the rigidity of the shaft 10 on the proximal side. Furthermore, the distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 in a cross section perpendicular to the longitudinal direction x1 in the proximal region A4 is preferably 15 times or less, more preferably 10 times or less, and even more preferably 5 times or less, the distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 in a cross section perpendicular to the longitudinal direction x1 in the distal region A3. By setting the upper limit of the ratio of the distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 in the proximal region A4 to the distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 in the distal region A3 within the above range, it is easy to ensure the distance between the outer edge of the inner lumen 150 and the outer surface of the shaft 10, and it is possible to make it less likely that an article such as a guidewire inserted into the inner lumen 150 will damage the partition between the inner lumen 150 and the outer surface of the shaft 10.

[0055] As shown in FIG. 5 , the shaft 10 preferably has an opening 170 in the proximal region A4, in a region between adjacent outer lumens 160 in the circumferential direction z1 of the inner lumen 150, that connects the inner lumen 150 to the outside of the shaft 10. In this case, a region is formed near the opening 170 where the inner lumen 150 approaches the outer surface of the shaft 10, as shown in FIG. 6 . By having the opening 170 in the proximal region A4 of the shaft 10, in a region between adjacent outer lumens 160, the balloon catheter 1 becomes a so-called rapid exchange type, making it easy to introduce items such as a guidewire or fluids into the inner lumen 150 through the opening 170. As a result, the procedure time using the balloon catheter 1 can be shortened, and minimal invasiveness can be improved.

[0056] The opening 170 is preferably located in a region between the first outer lumen 161 and the second outer lumen 162 in the circumferential direction z1 of the inner lumen 150. By locating the opening 170 in a region between the first outer lumen 161 and the second outer lumen 162, the opening 170 is located between the first outer lumen 161 and the second outer lumen 162, which are spaced apart in the circumferential direction z1 of the inner lumen 150. Therefore, when an article such as a guidewire is inserted through the opening 170, the article inserted through the opening 170 is less likely to come into contact with the partition wall that forms the inner lumen 150, making it possible to make the shaft 10 less likely to be damaged.

[0057] The opening 170 is preferably a guidewire port 50 for inserting a guidewire into the inner lumen 150. In other words, the balloon catheter 1 of the present invention is preferably a so-called rapid exchange type balloon catheter 1.

[0058] 6 , in a cross section perpendicular to the longitudinal direction x1 in the proximal region A4, the distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 is preferably greater than the shortest distance D23 between the outer edge of the inner lumen 150 and the outer edge of the shaft 10. The shortest distance D23 between the outer edge of the inner lumen 150 and the outer edge of the shaft 10 in the cross section perpendicular to the longitudinal direction x1 refers to the length of the shortest line connecting a point on the outer edge of the inner lumen 150 and a point on the outer edge of the shaft 10. Since the distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 is greater than the shortest distance D23 between the outer edge of the inner lumen 150 and the outer edge of the shaft 10, the inner lumen 150 is more likely to be configured close to the outer periphery of the shaft 10 in the proximal region A4. This makes it easier to increase the rigidity of the center of the shaft 10, and makes it easier for a force applied from the proximal side of the shaft 10 to be transmitted to the distal side.

[0059] In a cross section perpendicular to the longitudinal direction x1 in the proximal region A4, the distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 is preferably at least 1.1 times, more preferably at least 1.2 times, and even more preferably at least 1.3 times the shortest distance D23 between the outer edge of the inner lumen 150 and the outer edge of the shaft 10. By setting the lower limit of the ratio of the distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 in the proximal region A4 to the shortest distance D23 between the outer edge of the inner lumen 150 and the outer edge of the shaft 10 within the above range, the inner lumen 150 becomes closer to the outer periphery of the shaft 10 in the proximal region A4, and the rigidity of the central portion of the shaft 10 is likely to be increased. Furthermore, in a cross section perpendicular to the longitudinal direction x1 in the proximal region A4, the distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 is preferably 10 times or less, more preferably 7 times or less, and even more preferably 5 times or less, the shortest distance D23 between the outer edge of the inner lumen 150 and the outer edge of the shaft 10. By setting the upper limit of the ratio of the distance D22 between the center C10 of the shaft 10 and the center C150 of the inner lumen 150 in the proximal region A4 to the shortest distance D23 between the outer edge of the inner lumen 150 and the outer edge of the shaft 10 within the above range, it becomes easier to ensure the thickness of the partition between the inner lumen 150 and the outer edge of the shaft 10 in the proximal region A4, and the shaft 10 can be made less susceptible to damage when an article such as a guidewire is inserted into the inner lumen 150.

[0060] 6 , in a cross section perpendicular to the longitudinal direction x1 in the proximal region A4, the shortest distance D24 between the center C160 of an outer lumen 160 constituting the lumen group 600 and the center C10 of the shaft 10 is preferably greater than the center-to-center distance D25 between adjacent outer lumen 160 in the circumferential direction z1 of the inner lumen 150. The shortest distance D24 between the center C160 of the outer lumen 160 and the center C10 of the shaft 10 in a cross section perpendicular to the longitudinal direction x1 refers to the length of the shortest straight line in the outer lumen 160 connecting the center C160 of the outer lumen 160 and the center C10 of the shaft 10. In the proximal region A4, the shortest distance D24 between the center C160 of the outer lumen 160 and the center C10 of the shaft 10 is greater than the center-to-center distance D25 between adjacent outer lumens 160, which makes it easier for the outer lumen 160 to approach the outer periphery of the shaft 10 and makes it easier to increase the rigidity of the central portion of the shaft 10. As a result, the rigidity of the shaft 10 in the proximal region A4 is increased, making it easier for a force applied to the shaft 10 from the proximal side toward the distal side to be transmitted to the distal end 10d of the shaft 10.

[0061] In a cross section perpendicular to the longitudinal direction x1 in the proximal region A4, the shortest distance D24 between the center C160 of an outer lumen 160 constituting the lumen group 600 and the center C10 of the shaft 10 is preferably 1.1 times or more, more preferably 1.2 times or more, and even more preferably 1.3 times or more, the center-to-center distance D25 between adjacent outer lumens 160 in the circumferential direction z1 of the inner lumen 150. By setting the lower limit of the ratio of the shortest distance D24 between the center C160 of the outer lumen 160 and the center C10 of the shaft 10 to the center-to-center distance D25 between adjacent outer lumens 160 within the above range, it becomes easier to bring the outer lumen 160 closer to the outer periphery of the shaft 10 in the proximal region A4, and the rigidity of the central portion of the shaft 10 becomes easier to increase. Furthermore, in a cross section perpendicular to the longitudinal direction x1 in the proximal region A4, the shortest distance D24 between the center C160 of an outer lumen 160 constituting the lumen group 600 and the center C10 of the shaft 10 is preferably 10 times or less, more preferably 9 times or less, and even more preferably 8 times or less, the center-to-center distance D25 between adjacent outer lumens 160 in the circumferential direction z1 of the inner lumen 150. By setting the upper limit of the ratio of the shortest distance D24 between the center C160 of the outer lumen 160 and the center C10 of the shaft 10 to the center-to-center distance D25 between adjacent outer lumens 160 within the above range, the outer diameter of the shaft 10 is less likely to become excessively large, thereby enabling the balloon catheter 1 to be minimally invasive.

[0062] 6 , in a cross section perpendicular to the longitudinal direction x1 in the proximal region A4, the shortest distance D24 between the center C160 of the outer lumen 160 constituting the lumen group 600 and the center C10 of the shaft 10 is preferably greater than the shortest distance D26 between the outer edge of the outer lumen 160 and the outer edge of the shaft 10. The shortest distance D26 between the outer edge of the outer lumen 160 and the outer edge of the shaft 10 in the cross section perpendicular to the longitudinal direction x1 refers to the length of the shortest straight line in the outer lumen 160 connecting a point on the outer edge of the outer lumen 160 and a point on the outer edge of the shaft 10. Since the shortest distance D24 between the center C160 of the outer lumen 160 and the center C10 of the shaft 10 is greater than the shortest distance D26 between the outer edge of the outer lumen 160 and the outer edge of the shaft 10, it becomes easier to separate the outer lumen 160 from the center C10 of the shaft 10 in the proximal region A4. As a result, the rigidity of the central portion of the shaft 10 in the proximal region A4 is likely to increase, making it easier for a force applied from the proximal side of the shaft 10 to be transmitted to the distal side.

[0063] In a cross section perpendicular to the longitudinal direction x1 in the proximal region A4, the shortest distance D24 between the center C160 of the outer lumen 160 constituting the lumen group 600 and the center C10 of the shaft 10 is preferably at least 1.5 times, more preferably at least 2.0 times, and even more preferably at least 2.5 times the shortest distance D26 between the outer edge of the outer lumen 160 and the outer edge of the shaft 10. By setting the lower limit of the ratio of the shortest distance D24 between the center C160 of the outer lumen 160 and the center C10 of the shaft 10 to the shortest distance D26 between the outer edge of the outer lumen 160 and the outer edge of the shaft 10 within the above range, it becomes easier to increase the distance between the center C160 of the outer lumen 160 and the center C10 of the shaft 10, and this makes it easier to sufficiently increase the rigidity of the central portion of the shaft 10. Furthermore, in a cross section perpendicular to the longitudinal direction x1 in the proximal region A4, the shortest distance D24 between the center C160 of the outer lumen 160 constituting the lumen group 600 and the center C10 of the shaft 10 is preferably 20 times or less, more preferably 18 times or less, and even more preferably 15 times or less, the shortest distance D26 between the outer edge of the outer lumen 160 and the outer edge of the shaft 10. By setting the upper limit of the ratio of the shortest distance D24 between the center C160 of the outer lumen 160 and the center C10 of the shaft 10 to the shortest distance D26 between the outer edge of the outer lumen 160 and the outer edge of the shaft 10 within the above range, it becomes easier to ensure the thickness of the partition wall between the outer lumen 160 and the outer periphery of the shaft 10, and the partition wall of the outer lumen 160 is less likely to be damaged when the shaft 10 is bent, for example.

[0064] 3 and 5 , the inner lumen 150 is the guidewire lumen 13 through which a guidewire is inserted, and the outer lumen 160 constituting the lumen group 600 is an inflation lumen through which fluid supplied to the lumen of the balloon 20 passes, and preferably communicates with each of the lumens of the multiple balloons 20. By having the inner lumen 150 be the guidewire lumen 13 and the outer lumen 160 be the inflation lumen, it is possible to easily insert a guidewire into the inner lumen 150 and to make it less likely that the shaft 10 will be damaged when a guidewire is inserted into the inner lumen 150.

[0065] 1 and 2, the balloon catheter 1 preferably further includes a guidewire tube 40 having an inner cavity communicating with the guidewire lumen 13, the guidewire tube 40 being disposed within the inner cavity of the balloon 20. By including the guidewire tube 40 having an inner cavity communicating with the guidewire lumen 13, the balloon catheter 1 can be easily inserted with a guidewire, allowing the balloon catheter 1 to be delivered into the body along the guidewire. Furthermore, by inserting the guidewire through the guidewire tube 40, it is possible to prevent the guidewire from damaging the balloon 20, etc.

[0066] Examples of materials constituting the guidewire tube 40 include polyolefin resins such as polyethylene and polypropylene, polyamide resins such as nylon, polyester resins such as PET, aromatic polyetherketone resins such as PEEK, polyetherpolyamide resins, polyurethane resins, polyimide resins, fluorine-containing resins such as PTFE, PFA, and ETFE, and synthetic resins such as polyvinyl chloride resins. Among these, polyimide resins are preferred as the material constituting the guidewire tube 40. Using polyimide resin as the material constituting the guidewire tube 40 improves the lubricity of the guidewire tube 40. This facilitates inserting a guidewire through the lumen of the guidewire tube 40 and feeding the balloon catheter 1 into the body along the guidewire. The guidewire tube 40 may also have a multilayer structure including a braided layer such as a metal braid. The multilayer structure of the guidewire tube 40 can enhance the strength of the guidewire tube 40, its lubricity relative to the guidewire, and its kink resistance.

[0067] 1 , the proximal end of the guidewire tube 40 is preferably connected to the distal end of the shaft 10. When the shaft 10 has a distal shaft 15 and a proximal shaft 16, the proximal end of the guidewire tube 40 is preferably connected to the distal end of the distal shaft 15. Connecting the proximal end of the guidewire tube 40 to the distal end of the shaft 10 prevents the outer diameter of the balloon catheter 1 from becoming large, thereby improving minimal invasiveness.

[0068] 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 guidewire tube 40 and connected to the distal end of the balloon 20, or the guidewire tube 40 extending distally beyond the distal end 20d of the balloon 20 may function as the tip member 60.

[0069] As shown in Figures 1 and 2, a radiopaque marker 70 may be placed on the guidewire tube 40 inside the balloon 20 at the location where the balloon 20 is located in the longitudinal axis direction x1 so that the position of the balloon 20 can be confirmed under X-ray fluoroscopy.

[0070] Examples of positions on the guidewire tube 40 where the radiopaque marker 70 is located include the midpoint of the length from the distal end 20d of the balloon 20 to the proximal end 20p of the balloon 20, and the proximal end 203p and distal end 203d of the straight tube portion 203 of the balloon 20. Among these, the positions on the guidewire tube 40 where the radiopaque marker 70 is located are preferably the proximal end 203p and distal end 203d of the straight tube portion 203 of the balloon 20. By locating the radiopaque marker 70 on the guidewire tube 40 at the proximal end 203p and distal end 203d of the straight tube portion 203 of the balloon 20, the position of the balloon 20 can be easily confirmed. As a result, the balloon catheter 1 can be configured to easily apply pressure to the target location.

[0071] It is preferable that the shaft 10 has a coating applied to the outer wall of at least one of the distal shaft 15 and the proximal shaft 16, and it is more preferable that the shaft 10 has a coating applied to the outer wall of both the distal shaft 15 and the proximal shaft 16.

[0072] The coating applied to the shaft 10 can be a hydrophilic coating or a hydrophobic coating depending on the purpose, and can be applied by immersing the shaft 10 in a hydrophilic or hydrophobic coating agent, applying the hydrophilic or hydrophobic coating agent to the outer wall of the shaft 10, or covering the outer wall of the shaft 10 with the hydrophilic or hydrophobic coating agent, etc. The coating agent may contain drugs, additives, etc.

[0073] Examples of hydrophilic coating agents include hydrophilic polymers such as polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, methyl vinyl ether maleic anhydride copolymer, and hydrophilic coating agents made from any combination thereof.

[0074] 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.

[0075] The balloon catheter 1 of the present invention is preferably used for dilating an aortic valve, deforming a biological valve placed in the heart, or destroying a biological valve. Specifically, the balloon catheter 1 of the present invention is preferably used for dilating an aortic valve hardened by calcification or the like, or for deforming or destroying an artificial valve annulus of a biological valve to replace a deteriorated biological valve placed in the heart. The balloon catheter 1 of the present invention has a partition between the inner lumen 150 and the outer lumen 160 of the shaft 10 that is resistant to damage and fluids or objects pumped into the inner lumen 150 are resistant to ingress into the outer lumen 160. This allows for a structure having multiple balloons 20, making it easy to dilate a hardened aortic valve and deform or destroy a biological valve, which conventional balloon catheters were unable to sufficiently dilate.

[0076] This application claims the benefit of priority based on Japanese Patent Application No. 2023-102819, filed on June 22, 2023. The entire contents of the specification of Japanese Patent Application No. 2023-102819, filed on June 22, 2023, are incorporated herein by reference.

[0077] 1: Balloon catheter 5: Hub 6: Fluid injection section 10: Shaft 10d: Distal end of shaft 10p: Proximal end of shaft 13: Guidewire lumen 15: Distal shaft 16: Proximal shaft 20: Balloon 20d: Distal end of balloon 20p: Proximal end of balloon 201: Proximal sleeve section 201d: Distal end of proximal sleeve section 201p: Proximal end of proximal sleeve section 202: Proximal tapered section 202d: Distal end of proximal tapered section 202p: Proximal end of proximal tapered section 203: Straight tube section 203d: Distal end of straight tube section 203p: Proximal end of straight tube section 204: Distal tapered section 204d: Distal end of distal tapered section 204p: Proximal end of distal tapered section 205: Distal sleeve portion 205d: Distal end of distal sleeve portion 205p: Proximal end of distal sleeve portion 21: First balloon 22: Second balloon 40: Guidewire tube 50: Guidewire port 60: Distal tip member 70: Radiopaque marker 150: Inner lumen 160: Outer lumen 161: First outer lumen 162: Second outer lumen 163: Third outer lumen 170: Opening 600: Lumen group C10: Center of shaft C150: Center of inner lumen C160: Center of outer lumen C161: Center of first outer lumen C162: Center of second outer lumen C163: Center of third outer lumen D20: Distance between the center of the first outer lumen and the center of the second outer lumen D21: Distance between the center of the first outer lumen and the center of the third outer lumen D22: Distance between the center of the shaft and the center of the inner lumen D23: Shortest distance between the outer edge of the inner lumen and the outer edge of the shaft D24: Shortest distance between the center of the outer lumen and the center of the shaft D25: Distance between the centers of adjacent outer lumens D26: Shortest distance between the outer edge of the outer lumen and the outer edge of the shaft A3: Distal region A4: Proximal region L2: Length from the distal end of the balloon to the proximal end of the balloon

Claims

1. A catheter comprising a shaft extending in a longitudinal direction from a proximal side to a distal side, and a plurality of balloons disposed in a distal portion of the shaft, wherein the shaft, in a cross section perpendicular to the longitudinal direction at the distal end of the shaft, has an inner lumen and a lumen group composed of a plurality of outer lumen arranged side by side in a circumferential direction of the inner lumen outside the inner lumen, wherein, in the cross section perpendicular to the longitudinal direction at the distal end of the shaft, the lumen group includes a first outer lumen, a second outer lumen arranged adjacent to the first outer lumen in the circumferential direction of the inner lumen, and a third outer lumen arranged adjacent to the first outer lumen in the circumferential direction of the inner lumen and disposed on the opposite side to the second outer lumen, A balloon catheter, wherein, in a cross section perpendicular to the longitudinal direction, the shaft has a portion in which the distance between the center of the first outer lumen and the center of the second outer lumen is greater than the distance between the center of the first outer lumen and the center of the third outer lumen.

2. A balloon catheter as described in claim 1, wherein in a cross section perpendicular to the longitudinal direction, the shaft has a portion in which the distance between the center of the first outer lumen and the center of the second outer lumen is greater than the major axis of the outer lumen that constitutes the lumen group.

3. A balloon catheter as described in claim 1, wherein the shaft has a distal region, which is a region on the distal side, and a proximal region, which is a region located proximal to the distal region, and in a cross section perpendicular to the longitudinal direction in the proximal region, the distance between the center of the first outer lumen and the center of the second outer lumen is greater than the distance between the center of the first outer lumen and the center of the third outer lumen.

4. The balloon catheter according to claim 3, wherein the length of the proximal region is equal to or less than the length of the distal region in the longitudinal direction.

5. A balloon catheter as described in claim 1, wherein the shaft has a distal region, which is a region on the distal side, and a proximal region, which is a region located proximal to the distal region, and the distance between the center of the shaft and the center of the inner lumen in a cross section perpendicular to the longitudinal direction in the proximal region is greater than the distance between the center of the shaft and the center of the inner lumen in a cross section perpendicular to the longitudinal direction in the distal region.

6. A balloon catheter as described in claim 5, wherein the shaft has an opening in the proximal region, in the region between adjacent outer lumens in the circumferential direction of the inner lumen, that connects the inner lumen to the outside of the shaft.

7. The balloon catheter according to claim 6, wherein said opening is located in a region between said first outer lumen and said second outer lumen in the circumferential direction of said inner lumen.

8. The balloon catheter according to claim 5, wherein in a cross section perpendicular to the longitudinal direction in the proximal region, the distance between the center of the shaft and the center of the inner lumen is greater than the shortest distance between the outer edge of the inner lumen and the outer edge of the shaft.

9. A balloon catheter as described in claim 5, wherein in a cross section perpendicular to the longitudinal direction in the proximal region, the shortest distance between the center of one of the outer lumens constituting the group of lumens and the center of the shaft is greater than the center-to-center distance between adjacent outer lumens in the circumferential direction of the inner lumen.

10. A balloon catheter as described in claim 5, wherein in a cross section perpendicular to the longitudinal direction in the proximal region, the shortest distance between the center of the outer lumen that constitutes the group of lumens and the center of the shaft is greater than the shortest distance between the outer edge of the outer lumen and the outer edge of the shaft.

11. A balloon catheter as described in claim 1, wherein the inner lumen is a guidewire lumen through which a guidewire is inserted, and the outer lumen constituting the lumen group is an inflation lumen through which fluid supplied to the lumen of the balloon passes, and is connected to each of the lumens of the multiple balloons.

12. The balloon catheter according to claim 11, further comprising a guidewire tube having an inner cavity communicating with said guidewire lumen, said guidewire tube being disposed within the inner cavity of said balloon.

13. The balloon catheter according to any one of claims 1 to 12, which is used for expanding an aortic valve, deforming a biological valve placed in the heart, or destroying said biological valve.