Balloon catheter, method for manufacturing balloon catheter, and heat-shrinkable tube

Abstract

[Problem] To provide a balloon catheter, a method for manufacturing a balloon catheter, and a heat-shrinkable tube with which it is possible to prevent a decrease in the strength of a partition wall part that separates a guide wire lumen and an inflation lumen of a second shaft from each other. [Solution] A shaft part 100 of a balloon catheter 10 comprises a fusion part 140 at which a first shaft 110, a second shaft 120, and a third shaft 130 are fused to each other in the vicinity of the base end 113 of the first shaft. The shaft part has a partition wall part 150 that is formed along a predetermined range from the base end of the first shaft towards the tip side, and that separates a guide wire lumen 115 and an inflation lumen 125 of the second shaft. The partition wall part has a first region 150A that includes the base end 153 of the partition wall part, and a second region 150B located closer to the tip side than the first region of the partition wall part. The thickness of the second region with respect to the thickness of the first region is greater than 19% and less than 48%.

Description

Balloon catheter, method for manufacturing a balloon catheter, and heat-shrinkable tube

[0001] The present invention relates to a balloon catheter, a method for manufacturing a balloon catheter, and a heat-shrinkable tube.

[0002] Balloon catheters used for treatment, procedures, etc. in biological lumens such as blood vessels and various biological organs are widely known.

[0003] There are several types of balloon catheters. As one of them, a so-called rapid exchange type balloon catheter is configured such that a guide wire for assisting the movement of the balloon catheter within a biological lumen can be led out from a guide wire port formed at a predetermined position near the tip of the shaft portion of the balloon catheter.

[0004] The rapid exchange type balloon catheter includes a shaft (inner tube shaft) having a guide wire port and a guide wire lumen communicating with the guide wire port, and a plurality of shafts (tip shaft, intermediate shaft) formed around the guide wire lumen and having an inflation lumen communicating with the lumen of the balloon, and has a fusion portion fused in the vicinity of the guide wire port (see, for example, Patent Document 1).

[0005] Japanese Unexamined Patent Application Publication No. 2014-195487

[0006] When manufacturing the balloon catheter described in Patent Document 1, when connecting the three shafts, a heat-shrinkable tube is placed over each shaft, and the multiple shafts are connected by heat-sealing and pressurizing them through the heat-shrinkable tube. When the shafts are fused, a partition wall separating the guidewire lumen and the inflation lumen is formed in a certain range near the guidewire port and towards its tip due to the flow of the resin material constituting the shafts. In the manufacturing method using heat-shrinkable tubes, if the thermal load becomes excessively large when heating and pressurizing the shafts, the resin material forming the partition wall flows to a position further away from the guidewire port towards the tip. As a result, the thickness of the partition wall decreases drastically at a distance greater than a predetermined distance from the guidewire port towards the tip, which can lead to a decrease in the strength of the partition wall.

[0007] The present invention has been made in view of the above-mentioned problems, and aims to provide a balloon catheter, a method for manufacturing a balloon catheter, and a heat-shrinkable tube that can prevent a decrease in the strength of the partition wall separating the guidewire lumen and the inflation lumen of the second shaft.

[0008] The present invention can be achieved by any of the following means (1) to (10).

[0009] (1) A balloon catheter comprising a flexible shaft portion and a balloon disposed at the tip of the shaft portion, wherein the shaft portion comprises: a first shaft having a guidewire lumen and a guidewire port located at the proximal end of the guidewire lumen; a second shaft communicating with the lumen of the balloon and having a portion of an inflation lumen along the guidewire lumen; and a third shaft having a portion of the inflation lumen extending at least along the proximal end of the second shaft, wherein the shaft portion comprises a fused portion where the first shaft, the second shaft, and the third shaft are fused together near the proximal end of the first shaft; the shaft portion comprises a partition portion formed over a predetermined range from the proximal end of the first shaft toward the tip and separating the guidewire lumen and the inflation lumen of the second shaft; the partition portion comprises a first region including the proximal end of the partition portion and a second region located toward the tip of the partition portion than the first region. A balloon catheter in which the thickness of the second region is greater than 19% but less than 48% of the thickness of the first region.

[0010] (2) The balloon catheter according to (1), wherein the thickness of the second region is 14 μm or more and 27 μm or less.

[0011] (3) The balloon catheter according to (1) or (2), wherein the thickness of the region in (1) is 32 μm or more and 39 μm or less.

[0012] (4) The balloon catheter according to any one of (1) to (3), wherein the length of the first region is 4 mm and the length of the second region is 2 mm.

[0013] (5) The balloon catheter according to any one of (1) to (4), wherein the tip of the partition wall is located 7 mm away from the base end of the first shaft toward the tip.

[0014] (6) A method for manufacturing a balloon catheter comprising a shaft portion having a first shaft, a second shaft, and a third shaft, and a balloon disposed at the tip of the shaft portion, comprising a fusion step of fusing together each of the following near the base end of the first shaft: the first shaft forming a guidewire lumen and a guidewire port located at the base end of the guidewire lumen; the second shaft communicating with the lumen of the balloon and having a portion of the inflation lumen along the guidewire lumen; and the third shaft having a portion of the inflation lumen extending at least along the base end of the second shaft; and before the fusion step, comprising a step of inserting a first core through the guidewire lumen of the first shaft, and a step of inserting a second core through the inflation lumen of the second shaft and the inflation lumen of the third shaft. A method for manufacturing a balloon catheter, comprising: a step of arranging a first heat-shrinkable tube so as to cover the fusion points of the first shaft, the second shaft, and the third shaft before the fusion step; and an arrangement step of arranging a second heat-shrinkable tube so as to cover the first heat-shrinkable tube, wherein in the arrangement step, the second heat-shrinkable tube is arranged in a range of 4 mm or less from the base end to the tip side of the first shaft; and in the fusion step, heat is applied to the first heat-shrinkable tube and the second heat-shrinkable tube to shrink their diameters and fuse the first shaft, the second shaft, and the third shaft together.

[0015] (7) The method for manufacturing a balloon catheter according to claim 6, wherein in the arrangement step, the first heat shrink tube is arranged to extend longer toward the tip than the second heat shrink tube.

[0016] (8) A heat shrinkable tube used in the manufacture of a balloon catheter comprising a shaft portion having a first shaft, a second shaft, and a third shaft, and a balloon disposed at the tip of the shaft portion, wherein the heat shrinkable tube is used when each of the first shaft having a guidewire lumen and a guidewire port located at the proximal end of the guidewire lumen, the second shaft communicating with the lumen of the balloon and having a portion of the inflation lumen along the guidewire lumen, and the third shaft having a portion of the inflation lumen extending at least along the proximal end of the second shaft, is fused together near the proximal end of the first shaft, and the length along the axial direction of the shaft portion is 4 mm.

[0017] (9) The heat shrink tube according to (8), wherein the heat shrink tube is made of silicone having a thickness of 0.2 mm or more and 0.45 mm or less after heat shrinkage.

[0018] (10) The heat shrink tube according to (8) or (9), wherein the heat shrink tube has a shrinkage rate of 50% before and after heating.

[0019] According to the balloon catheter, method for manufacturing a balloon catheter, and heat-shrinkable tube of the present invention, it is possible to prevent a decrease in the strength of the partition wall separating the guidewire lumen and the inflation lumen of the second shaft.

[0020] This figure shows a balloon catheter according to an embodiment. This is a cross-sectional view of the area indicated by the dashed line 2A in Figure 1, and is an enlarged cross-sectional view of the area near the tip of the balloon catheter. This is a cross-sectional view of the area indicated by the dashed line 3A in Figure 1, and is an enlarged cross-sectional view of the area near the guidewire port of the balloon catheter. This is a cross-sectional view along the line 4A-4A shown by arrow 4A in Figure 3. This is a cross-sectional view for explaining the manufacturing method of the balloon catheter according to an embodiment. This is a cross-sectional view for explaining the manufacturing method of the balloon catheter according to an embodiment. This is a table for explaining the septum thickness reduction rate of the balloon catheter according to the example and comparative example. This is a table for explaining the septum thickness (thickness of the first region and thickness of the second region) of the balloon catheter according to the example and comparative example. This is a table for explaining the pressure resistance test results of the balloon catheter according to the example and comparative example.

[0021] Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. The embodiments shown herein are illustrative examples for embodying the technical idea of ​​the present invention and do not limit the present invention. Furthermore, all other implementable forms, examples, and operational techniques that can be conceived by those skilled in the art without departing from the spirit of the present invention are included in the scope and spirit of the present invention, as well as in the claims and their equivalents.

[0022] Furthermore, the drawings attached to this specification may be schematically represented with changes to scale, aspect ratio, shape, etc., from the actual object for the sake of illustration and ease of understanding, but these are merely examples and do not limit the interpretation of the present invention.

[0023] For the sake of clarity, the following directions are defined in this specification.

[0024] The "axial direction" is defined as the direction of extension of the shaft portion 100. The "circumferential direction" is defined as the rotational direction based on the cross-section perpendicular to the axis of the shaft portion 100 of the balloon catheter 10. In each figure, arrows X1-X2 indicate the axial direction of the balloon catheter 10, arrows Y1-Y2 indicate the depth direction perpendicular to the axial direction, and arrows Z1-Z2 indicate the height direction perpendicular to both the axial and depth directions. The cross-section perpendicular to the axial direction (Y1-Y2 / Z1-Z2 cross-section) is defined as the cross-section perpendicular to the axis.

[0025] In the balloon catheter 10, the side on which the hub 300 is located is referred to as the "proximal end." In the balloon catheter 10, the side opposite to the proximal end and which is introduced into the body is referred to as the "proximal end." The "proximal end" refers to the portion that includes a certain range extending from the tip (extent) towards the proximal end, and the "proximal end" refers to the portion that includes a certain range extending from the proximal end (very basal end) towards the proximal end.

[0026] (Balloon catheter 10) As shown in Figures 1 to 3, the balloon catheter 10 comprises a flexible shaft portion 100 and a balloon 200 positioned at the tip of the shaft portion 100.

[0027] The balloon catheter 10 according to this embodiment is configured as a medical device that treats narrowed areas (lesion sites) by inserting the shaft portion 100 into a biological lumen and expanding the balloon 200 located at the tip of the shaft portion 100 at the narrowed area (lesion site).

[0028] The balloon catheter 10 can be configured, for example, as a PTCA dilation balloon catheter used to widen narrowed coronary arteries. However, the balloon catheter 10 can also be configured for use in treating and improving narrowings formed in other blood vessels, bile ducts, trachea, esophagus, other parts of the digestive tract, urethra, ear, nose, and throat lumen, and other organs.

[0029] The balloon catheter 10 is configured as a rapid exchange type catheter, with a guidewire port 113a formed near the tip of the shaft portion 100, through which a guidewire GW can enter and exit.

[0030] (Shaft section 100) As shown in Figures 1 to 3, the shaft section 100 has a first shaft (base inner tube shaft) 110, a second shaft (tip shaft) 120, and a third shaft (intermediate shaft) 130.

[0031] As shown in Figures 2 and 3, the first shaft 110 is equipped with a guide wire port 113a located at the base end of the guide wire GW and the guide wire lumen 115.

[0032] The first shaft 110 extends to the vicinity of the tip 201 of the balloon 200. The tip 201 of the balloon 200 is connected to the vicinity of the tip 111 of the first shaft 110.

[0033] A predetermined tip 160 can be attached to the tip of the first shaft 110. The tip 160 can be made of, for example, a flexible resin material.

[0034] A contrast marker 170 can be attached to the first shaft 110 to indicate a predetermined position of the balloon 200 (for example, the axial center position of the straight portion of the balloon 200). The contrast marker 170 can be made of a metal such as platinum, gold, silver, iridium, titanium, or tungsten, or an alloy thereof.

[0035] The guidewire port 113a can be formed at a base end opening located at the base end 113 of the first shaft 110. The guidewire GW can be inserted into the guidewire lumen 115 from the tip opening 111a of the first shaft 110 (or the tip opening of the tip if the first shaft 110 is equipped with a tip 160). The guidewire GW inserted into the guidewire lumen 115 can be led out to the outside of the shaft portion 100 via the guidewire port 113a which communicates with the guidewire lumen 115.

[0036] As shown in Figures 2 and 3, the second shaft 120 communicates with the lumen 205 of the balloon 200 and includes a portion of the inflation lumen 125 that extends along at least a portion of the guidewire lumen 115.

[0037] As shown in Figure 2, the tip 121 of the second shaft 120 is positioned closer to the proximal end than the tip 111 of the first shaft 110. The proximal end 203 of the balloon 200 is connected to the vicinity of the tip 121 of the second shaft 120. The inflation lumen 125 of the second shaft 120 is in communication with the lumen 205 of the balloon 200 via the tip opening 121a of the second shaft 120.

[0038] As shown in Figures 2 and 3, the third shaft 130 includes a portion of the inflation lumen 135 that extends along at least the base end 123 of the second shaft 120.

[0039] The inflation lumen 125 of the second shaft 120 is in communication with the inflation lumen 135 of the third shaft 130. Another shaft member (base shaft) connecting the third shaft 130 and the hub 300 can be connected to the base end of the third shaft 130. The inflation lumen 135 of the third shaft 130 is in communication with the inside of the hub 300 via the other shaft member.

[0040] Furthermore, it is possible to place rod-shaped reinforcing members made of a metal material or the like with higher rigidity than the shaft portion 100 in a portion of the base end of the inflation lumen 135 of the third shaft 130 and inside the other shafts.

[0041] Each shaft 110, 120, and 130 can be made of a hollow tubular member having a lumen. Each shaft 110, 120, and 130 can be made of a heat-sealable resin material. As such materials, for example, polyolefins such as polyethylene, polypropylene, ethylene-propylene copolymer, and ethylene-vinyl acetate copolymer, thermoplastic resins such as flexible polyvinyl chloride, various elastomers such as polyurethane elastomer, polyamide elastomer, and polyester elastomer, and crystalline plastics such as polyamide, crystalline polyethylene, and crystalline polypropylene can be used.

[0042] As shown in Figure 3, the shaft portion 100 includes a fused portion 140 where the first shaft 110, the second shaft 120, and the third shaft 130 are fused together near the base end 113 of the first shaft 110.

[0043] In FIG. 3, dots are provided on the fusion part 140. In FIG. 3, for the sake of explanation, the boundaries of the respective shafts 110, 120, and 130 in the vicinity of the fusion part 140 are clearly illustrated. However, when the fusion part 140 is formed by heat fusion described later, in the vicinity of the fusion part 140, the resin materials, which are the constituent materials of the respective shafts 110, 120, and 130, melt and merge with each other to become integral. Therefore, actually, the boundaries of the respective shafts 110, 120, and 130 do not clearly exist or exist in an ambiguous state as shown in the cross-sectional view orthogonal to the axis in FIG. 4.

[0044] As shown in FIGS. 3 and 4, the shaft part 100 is formed over a predetermined range from the proximal end 113 of the first shaft 110 toward the distal end side, and has a partition part 150 that separates between the guide wire lumen 115 and the inflation lumen 125 of the second shaft 120.

[0045] The partition part 150 has a predetermined length along the axial direction. As shown in FIG. 4, in the axial range where the partition part 150 is formed, on the cross-section orthogonal to the axis, the guide wire lumen 115 and the inflation lumen 135 are arranged in a separated state with the partition part 150 interposed therebetween. The inflation lumen 135 is configured to exhibit a non-circular cross-sectional shape such as a crescent or a semi-circle in the range where the partition part 150 is formed due to the influence of pressure and the like applied when performing heat fusion described later. However, there is no particular limitation on the specific cross-sectional shape of the inflation lumen 135.

[0046] As shown in FIG. 3, the partition part 150 has a first region 150A including the proximal end 153 of the partition part 150, and a second region 150B located on the distal end side of the first region 150A of the partition part 150.

[0047] In the present embodiment, the proximal end of the first region 150A and the proximal end 153 of the partition part 150 are in the same axial position, and the distal end of the second region 150B and the distal end 151 of the partition part 150 are in the same axial position.

[0048] When the fusion part 140 is formed by the manufacturing method according to the present embodiment described below, a plurality of regions 150A and 150B with different thicknesses t are formed in the partition part 150. The thickness t of the partition part 150 can be defined by the dimension of the linear distance between the lower end position arranged on the most inflation lumen 135 side of the guide wire lumen 115 and the upper end position arranged on the most guide wire lumen 115 side of the inflation lumen 135 in the axial cross-sectional view shown in FIG. 4.

[0049] When the shrinkage force associated with thermal shrinkage is applied to each of the shafts 110, 120, and 130 from each of the heat shrinkable tubes 410 and 420 when forming the fusion part 140 as described below, a flow of the resin material constituting the second shaft 120 and the third shaft 130 occurs from the proximal end side to the distal end side of the first shaft 110 (see FIG. 6). At this time, the starting point of the flow of the resin material constituting the second shaft 120 and the third shaft 130 is near the guide wire port 113a located at the proximal end 113 of the first shaft 110. Therefore, the first region 150A of the partition part 150 formed from the vicinity of the guide wire port 113a (near the proximal end 113 of the first shaft 110) toward the distal end side in the axial direction is formed with a relatively large wall thickness. Thereby, it is difficult for the partition part 150 to have a decrease in strength in the first region 150A. On the other hand, the amount of the resin material flowing into the second region 150B located on the distal end side of the first region 150A is less than that of the first region 150A. Therefore, it is considered that the second region 150B is more likely to have a decrease in strength compared to the first region 150A.

[0050] In the present embodiment, in order to prevent the occurrence of the above problems, the ratio of the thicknesses of the two is set so that the second region 150B is not formed with an excessively small thickness with respect to the first region 150A. Specifically, the thickness of the second region 150B with respect to the thickness of the first region 150A (thickness of the second region 150B / thickness of the first region 150A × 100 [%]. Hereinafter, referred to as "partition thickness reduction rate") is greater than 19% and less than 48%.

[0051] By having the above-mentioned septum thickness reduction rate, the balloon catheter 10 can suppress a decrease in the strength of the second region 150B while suitably maintaining a state in which the guidewire lumen 115 and the inflation lumen 135 are appropriately separated by the septum portion 150 (non-communication state).

[0052] Furthermore, the reduction rate of the partition wall thickness is preferably greater than 19% and less than 48%, and more preferably greater than 19% and less than 36%.

[0053] Furthermore, when setting the partition wall thickness reduction rate within the above range, the thickness of the second region 150B can be set, for example, to 14 μm or more and 27 μm or less. By forming the thickness of the second region 150B with such dimensions, a reduction in the strength of the second region 150B can be effectively prevented.

[0054] Furthermore, when setting the partition wall thickness reduction rate within the above range, the thickness of the first region 150A can be set, for example, to 32 μm or more and 39 μm or less. By forming the thickness of the first region 150A with such dimensions, a reduction in the strength of the first region 150A can be effectively prevented.

[0055] The length (axial length) of the first region 150A can be formed to 4 mm. The length (axial length) of the second region 150B can be formed to 2 mm. As described later, by forming the fused portion 140 using the respective heat shrink tubes 410 and 420, it is possible to form the partition wall portion 150 having the aforementioned partition wall thickness reduction ratio while forming each region 150A and 150B to the above lengths.

[0056] The tip 151 of the partition wall 150 can be positioned 7 mm away from the base end of the first shaft 110 (the base end of the guide wire port 113a) toward the tip. By forming the partition wall 150 in this way, it is possible to prevent the partition wall 150 from being formed excessively long toward the tip, which would reduce the strength of the second region 150B. In addition, the partition wall 150 can maintain an appropriate separation (non-communication) between the guide wire lumen 115 and the inflation lumen 135.

[0057] In this embodiment, the first region 150A is formed with a length of 4 mm from the base end of the first shaft 110 toward the tip, and the second region 150B is formed with a length of 2 mm from the boundary position between the first region 150A and the second region 150B toward the tip. For example, if the partition wall 150 is formed with a length of 7 mm, a third region can be provided in the partition wall 150 that extends further toward the tip than the second region 150B.

[0058] (Balloon 200) As shown in Figure 2, the balloon 200 is connected to the first shaft 110 and the second shaft 120. Note that Figure 2 shows the balloon 200 in an expanded state as an example.

[0059] The balloon 200 expands radially in the direction of the first shaft 110 by injecting an expansion fluid into the lumen 205 partitioned between the balloon 200 and the first shaft 110. As the expansion fluid, for example, a mixture of contrast agent and physiological saline solution or a gas such as air can be used.

[0060] As constituent materials for balloon 200, for example, polyethylene, polypropylene, ethylene-propylene copolymer polyolefin, polyester such as polyethylene terephthalate, thermoplastic resins such as polyvinyl chloride, ethylene-vinyl acetate copolymer, cross-linked ethylene-vinyl acetate copolymer, and polyurethane, polyamide, polyamide elastomer, polystyrene elastomer, silicone rubber, latex rubber, etc. can be used.

[0061] (Hub 300) As shown in Figure 1, a hub 300 is connected to the proximal end of the shaft portion 100, to which a supply device (e.g., an indeflater) for controlling the movement of fluid in and out of each inflation lumen 125, 135 can be connected. A kink protector known in the field of catheters can be attached to the tip end of the hub 300.

[0062] The balloon 200 expands when expansion fluid is supplied to each inflation lumen 125, 135 via the hub 300, and deflates when the expansion fluid is discharged via the hub 300.

[0063] (Method for manufacturing the balloon catheter 10) Next, the method for manufacturing the balloon catheter 10 according to this embodiment will be described.

[0064] In this embodiment, the process of connecting each shaft 110, 120, and 130 by fusion bonding will be mainly described.

[0065] In the manufacturing method of the balloon catheter 10, an example using the heating device 600 (for example, a heating oven) shown in Figures 5 and 6 will be described.

[0066] The heating device 600 has an internal space into which a portion of each shaft 110, 120, and 130 (a certain range including the guide wire port 113a to be fused) can be inserted. A positioning section 610 can be provided in the internal space of the heating device 600 to position each shaft 110, 120, and 130 at a predetermined position in the internal space by abutting the base end face of the first heat shrink tube 410, which will be described later, against it.

[0067] As shown in Figure 5, the worker performing the manufacturing work assembles the shafts 110, 120, and 130. Specifically, the first shaft 110 is inserted through the second shaft 120, and the shafts 110, 120, and 130 are positioned such that a portion of the tip 131 of the third shaft 130 overlaps with the first shaft 110 and the second shaft 120 in the circumferential direction near the base end 113 of the first shaft 110. At this time, the shafts 120 and 130 are positioned so that the inflation lumen 125 of the second shaft 120 and the inflation lumen 135 of the third shaft 130 are in communication.

[0068] When commencing the manufacturing method according to this embodiment, the balloon 200 may or may not be connected to the first shaft 110.

[0069] The worker inserts the first mandrel 510 into the guide wire lumen 115 of the first shaft 110. The worker also inserts the second mandrel 520 into the inflation lumen 125 of the second shaft 120 and the inflation lumen 135 of the third shaft 130. By performing the fusion process described later with the mandrels 510 and 520 inserted into each lumen 115, 125, and 135, it is possible to prevent the lumens 115, 125, and 135 from becoming blocked during the fusion process.

[0070] Each core metal 510, 520 can be a known metal rod-shaped member (wire-shaped member) having a predetermined heat resistance.

[0071] Before the fusion process, the worker performs the following steps: positioning the first heat shrink tube 410 so as to cover the fusion points (the areas where the fusion portion 140 will be formed) of the first shaft 110, the second shaft 120, and the third shaft 130; and positioning the second heat shrink tube 420 so as to cover the first heat shrink tube 410.

[0072] As the first heat shrinkable tube 410, for example, a resin tube with heat shrinkability whose main material (primary material) is made of polyolefin can be used. The first heat shrinkable tube 410 can have an axial length of 10 mm, an inner diameter of 1.45 mm or more and 1.75 mm or less before heat shrinkage, an inner diameter of 0.48 mm or more and 0.58 mm or less after heat shrinkage, a wall thickness of 0.36 mm or more and 0.46 mm or less after heat shrinkage, and a shrinkage rate of 50% before and after heating.

[0073] As shown in Figure 5, the base end 413 of the first heat shrink tube 410 can be positioned at approximately the same location as the base end of the first shaft 110. If a first heat shrink tube 410 with an axial length of 10 mm is used, the tip 411 of the first heat shrink tube 410 can be positioned 10 mm away from the base end of the first shaft 110 towards the tip.

[0074] The second heat shrinkable tube 420 can be, for example, a heat-shrinkable resin tube whose main material (primary material) is silicone. The second heat shrinkable tube 420 can have an axial length of 4 mm, an inner diameter of 1.8 mm to 2.4 mm before heat shrinkage, an inner diameter of 0.7 mm to 1.1 mm after heat shrinkage, a wall thickness of 0.2 mm to 0.4 mm after heat shrinkage, and a shrinkage rate of 50% before and after heating.

[0075] The base end 423 of the second heat shrink tube 420 can be positioned at approximately the same location as the base end of the first shaft 110 (the same location as the base end 413 of the first heat shrink tube 410). If a second heat shrink tube 420 with an axial length of 4 mm is used, the tip 421 of the second heat shrink tube 420 can be positioned 4 mm away from the base end of the first shaft 110 towards the tip.

[0076] In this embodiment, the length of the first heat shrink tubing 410 is 10 mm, and the length of the second heat shrink tubing 420 is 4 mm. Furthermore, the base end 413 of the first heat shrink tubing 410 and the base end 423 of the second heat shrink tubing 420 are positioned at approximately the same location in the axial direction. Therefore, the worker can position the second heat shrink tubing 420 within a range of 4 mm or less from the base end 413 toward the tip of the first heat shrink tubing 410.

[0077] Furthermore, as described above, since the length of the first heat shrink tube 410 is 10 mm and the length of the second heat shrink tube 420 is 4 mm, the worker can position the first heat shrink tube 410 to extend further toward the tip than the second heat shrink tube 420. With the heat shrink tubes 410 and 420 positioned in this manner, as shown in Figure 5, each shaft 110, 120, and 130 is covered by the first heat shrink tube 410 only in a predetermined area toward the tip 421 of the second heat shrink tube 420.

[0078] The worker assembles the shafts 110, 120, and 130, the core metals 510 and 520, and the heat shrink tubes 410 and 420 as described above, and then places these components inside the heating device 600. When placing the components inside the heating device 600, the worker can position each component in a predetermined position within the heating device 600 by abutting the base end face of the first heat shrink tube 410 against the positioning section 610 of the heating device 600.

[0079] Next, the worker operates the heating device 600 to apply heat to each of the heat shrink tubes 410 and 420. The temperature at which the heating device 600 heats each of the heat shrink tubes 410 and 420 can be arbitrarily set according to the material of each shaft 110, 120, and 130, the material of each of the heat shrink tubes 410 and 420, etc., but for example it is 180° to 190°.

[0080] Each heat-shrinkable tube 410, 420 deforms to shrink in diameter when heated, and as shown in Figure 6, heats and pressurizes predetermined parts of each shaft 110, 120, 130 (indicated by arrow P). In the parts of each shaft 110, 120, 130 that are heated and pressurized by each heat-shrinkable tube 410, 420, the resin material that makes up the structure melts and fuses with the other material. At this time, a partition wall 150 is formed between the guide wire lumen 115 and the inflation lumen 135. Note that the heating device 600 is not shown in Figure 6.

[0081] When heat-sealing each shaft 110, 120, and 130, pressure is applied to the area surrounded by the first heat-shrinkable tube 410 and the second heat-shrinkable tube 420 from the two heat-shrinkable tubes 410 and 420, which shrink in diameter as they are heated. Therefore, in the area described above (i.e., the area where the second heat-shrinkable tube 420 is positioned in the axial direction), the resin material is likely to move toward the tip. In this embodiment, since the second heat-shrinkable tube 420 has a length of 4 mm in the axial direction, the partition wall portion 150 is formed over a range of at least 4 mm from the base end of the first shaft 110. Furthermore, since the resin moves a predetermined distance toward the tip beyond the second heat-shrinkable tube 420, the partition wall portion 150 is ultimately formed to extend to a position approximately 6 mm to 7 mm toward the tip from the base end of the first shaft 110. As a result, a relatively thick first region 150A is formed in the partition wall 150 at a position 4 mm from the base end of the first shaft 110, and a relatively thin second region 150B is formed in a range of 2 mm to 3 mm from the tip of the first region 150A toward the tip.

[0082] By following the above procedure, the worker can form a shaft portion 100 that includes regions 150A and 150B and has a partition wall portion 150 that separates the guide wire lumen 115 and the inflation lumen 135.

[0083] As described above, the balloon catheter 10 according to this embodiment is a balloon catheter comprising a flexible shaft portion 100 and a balloon 200 disposed at the tip of the shaft portion 100, wherein the shaft portion 100 has a first shaft 110 having a guidewire lumen 115 and a guidewire port 113a located at the proximal end of the guidewire lumen 115, a second shaft 120 communicating with the lumen 205 of the balloon 200 and having a part of the inflation lumen 125 along the guidewire lumen 115, and a third shaft 130 having a part of the inflation lumen 135 extending along at least the proximal end 123 of the second shaft 120, and The shaft portion 100 includes a fused portion 140 where the first shaft 110, the second shaft 120, and the third shaft 130 are fused together near the base end 113 of the first shaft 110. The shaft portion 100 is formed over a predetermined range from the base end 113 of the first shaft 110 toward the tip, and has a partition wall portion 150 that separates the guide wire lumen 115 from the inflation lumen 125 of the second shaft 120. The partition wall portion 150 has a first region 150A including the base end 153 of the partition wall portion 150, and a second region 150B located toward the tip of the partition wall portion 150, with the thickness of the second region 150B being greater than 19% but less than 48% of the thickness of the first region 150A.

[0084] Furthermore, the method for manufacturing the balloon catheter 10 according to this embodiment is a method for manufacturing the balloon catheter 10 comprising a shaft portion 100 having a first shaft 110, a second shaft 120, and a third shaft 130, and a balloon 200 disposed at the tip of the shaft portion 100, wherein the shaft portion 100 has a fusion step in which each of the following is fused together near the base end 113 of the first shaft 110: the first shaft 110 which forms a guide wire lumen 115 and a guide wire port 113a located at the base end of the guide wire lumen 115, the second shaft 120 which communicates with the lumen 205 of the balloon 200 and has a part of the inflation lumen 125 along the guide wire lumen 115, and the third shaft 130 which has a part of the inflation lumen 135 extending along at least the base end 123 of the second shaft 120, and before the fusion step, the guide wire of the first shaft 110 The process includes the steps of inserting the first core metal 510 into the yalumen 115, and inserting the second core metal 520 into the inflation lumen 125 of the second shaft 120 and the inflation lumen 135 of the third shaft 130, and before the fusion process, the steps include arranging the first heat shrink tube 410 so as to cover the fusion points of the first shaft 110, the second shaft 120, and the third shaft 130, and arranging the second heat shrink tube so as to cover the first heat shrink tube 410. The process includes a placement step of arranging the 420, in which the second heat shrink tube 420 is placed in a range of 4 mm or less from the base end 113 toward the tip of the first shaft 110, and in the fusion step, heat is applied to the first heat shrink tube 410 and the second heat shrink tube 420 to reduce their diameter, thereby fusing the first shaft 110, the second shaft 120, and the third shaft 130 together.

[0085] Furthermore, the second heat shrinkable tube 420 according to this embodiment is a heat shrinkable tube used in the manufacture of a balloon catheter 10 comprising a shaft portion 100 having a first shaft 110, a second shaft 120, and a third shaft 130, and a balloon 200 disposed at the tip of the shaft portion 100, wherein the second heat shrinkable tube 420 is used when each of the first shaft 110 having a guidewire lumen 115 and a guidewire port 113a located at the proximal end of the guidewire lumen 115, the second shaft 120 communicating with the lumen 205 of the balloon 200 and having a part of the inflation lumen 125 along the guidewire lumen 115, and the third shaft 130 having a part of the inflation lumen 135 extending at least along the proximal end of the second shaft 120 is fused together near the proximal end 113 of the first shaft 110, and has a length along the axial direction of the shaft portion 100 of 4 mm.

[0086] According to the balloon catheter 10, the method for manufacturing the balloon catheter 10, and the second heat shrink tube 420 of this embodiment described above, it is possible to prevent a decrease in the strength of the partition wall 150 that separates the guide wire lumen 115 and the inflation lumen 125 of the second shaft 120.

[0087] (Examples) Next, examples of the shaft portion of the present invention that were carried out to confirm the effects of the present invention will be described. However, the present invention is not limited to the contents of the examples described below.

[0088] As examples and comparative examples of the present invention, six shaft portions, Samples No. 1 to 6, were prepared.

[0089] In the embodiment, a second heat-shrinkable tube with a length of 4.0 mm was used, and a shaft section with a partition wall was manufactured based on the procedure described in the manufacturing method above (the procedure described in Figures 5 and 6). In the comparative example, a second heat-shrinkable tube with a length of 10 mm was used, and a shaft section with a partition wall was manufactured based on the same procedure. Other manufacturing conditions (arrangement of each component, etc.) are the same as those described in the embodiment above, and are therefore omitted.

[0090] Figure 7 shows the percentage reduction in partition wall thickness for each sample in the examples and comparative examples.

[0091] The partition wall thickness reduction rate was calculated by defining the first region as the area from the base end to the tip end of the partition wall up to 4 mm, and the second region as the area from the boundary of the first region towards the tip end up to 2 mm. The average partition wall thickness reduction rate for the example samples was 34.0%, and the average partition wall thickness reduction rate for the comparative example samples was 71.8%.

[0092] Figure 8 shows the measurement results of the thickness of the partition wall portion for each sample in the examples and comparative examples.

[0093] In the example sample, the minimum thickness of the first region of the partition wall was 34 mm, and the maximum thickness of the first region was 38 mm. In the example sample, the minimum thickness of the second region of the partition wall was 19 mm, and the maximum thickness of the second region was 25 mm. In the comparative example sample, the minimum thickness of the first region of the partition wall was 27 mm, and the maximum thickness of the first region was 36 mm. In the comparative example sample, the minimum thickness of the second region of the partition wall was 7 mm, and the maximum thickness of the second region was 12 mm.

[0094] From the above results, it was confirmed that the minimum and maximum thickness values ​​of the first region of the sample in the example were greater than the minimum and maximum thickness values ​​of the first region of the sample in the comparative example. Furthermore, it was confirmed that the minimum and maximum thickness values ​​of the second region of the sample in the example were greater than the minimum and maximum thickness values ​​of the second region of the sample in the comparative example.

[0095] Figure 9 shows the test results of the pressure resistance tests performed on each sample. In this pressure resistance test, a balloon catheter containing each sample was manufactured, and an expansion fluid (air) was injected into the balloon lumen through the inflation lumen of the second shaft and the inflation lumen of the third shaft. The occurrence of leakage from the septum and the pressure at which leakage occurred (pressure resistance [atm]) were measured. A linear pressurization method was used, starting at 1 atm and increasing the pressurization amount by 1 atm at a time until it reached a maximum of 40 atm.

[0096] The average pressure resistance of the sample in the example was 30.08 atm. The average pressure resistance of the sample in the comparative example was 28.91 atm. These results confirm that the sample in the example exhibited higher pressure resistance performance than the sample in the comparative example.

[0097] Based on the results of the examples and comparative examples described above, it was confirmed that the shaft portion manufactured using a second heat shrink tubing with a length of 4.0 mm could form a larger thickness in the first and second regions of the partition wall compared to the shaft portion manufactured using a second heat shrink tubing with a length of 10.0 mm, thereby improving the pressure resistance performance (strength of the partition wall) of the shaft portion.

[0098] Although the balloon catheter, method for manufacturing a balloon catheter, and heat-shrinkable tubing according to the present invention have been described through embodiments and examples, the present invention is not limited to the configurations described in embodiments and examples, and can be modified as appropriate based on the claims.

[0099] This application is based on Japanese Patent Application No. 2024-168613, filed on 27 September 2024, the disclosures of which are incorporated herein by reference in their entirety.

[0100] 10 Balloon catheter 100 Shaft 110 First shaft 111 Tip of first shaft 113 Base of first shaft 113a Guidewire port 115 Guidewire lumen 120 Second shaft 121 Tip of second shaft 121a Opening at the tip of second shaft 123 Base of second shaft 125 Inflation lumen 130 Third shaft 131 Tip of third shaft 135 Inflation lumen 140 Fused section 150 Septal section 150A First region 150B Second region 151 Tip of septum 153 Base of septum 200 Balloon 205 Lumen of balloon 300 Hub 410 First heat shrink tubing 411 Tip of first heat shrink tubing 413 Base of first heat shrink tubing 420 Second heat shrink tubing 421 Tip of second heat shrink tubing 423 Base of second heat shrink tubing 510 First mandrel 520 Second mandrel 600 Heating device 610 Positioning part GW Guide wire t Thickness of partition wall

Claims

1. A balloon catheter comprising a flexible shaft portion and a balloon disposed at the tip of the shaft portion, wherein the shaft portion comprises: a first shaft having a guidewire lumen and a guidewire port located at the proximal end of the guidewire lumen; a second shaft communicating with the lumen of the balloon and having a portion of an inflation lumen along the guidewire lumen; and a third shaft having a portion of the inflation lumen extending at least along the proximal end of the second shaft, wherein the shaft portion comprises a fused portion where the first shaft, the second shaft, and the third shaft are fused together near the proximal end of the first shaft; the shaft portion comprises a partition portion formed over a predetermined range from the proximal end of the first shaft toward the tip and separating the guidewire lumen from the inflation lumen of the second shaft; the partition portion comprises a first region including the proximal end of the partition portion and a second region located toward the tip of the partition portion than the first region. A balloon catheter in which the thickness of the second region is greater than 19% but less than 48% of the thickness of the first region.

2. The balloon catheter according to claim 1, wherein the thickness of the second region is 14 μm or more and 27 μm or less.

3. The balloon catheter according to claim 1 or claim 2, wherein the thickness of the region in 1 is 32 μm or more and 39 μm or less.

4. The balloon catheter according to claim 1, wherein the length of the first region is 4 mm and the length of the second region is 2 mm.

5. The balloon catheter according to claim 1, wherein the tip of the partition wall is positioned 7 mm away from the base end of the first shaft toward the tip.

6. A method for manufacturing a balloon catheter comprising a shaft portion having a first shaft, a second shaft, and a third shaft, and a balloon disposed at the tip of the shaft portion, the method comprising a fusion step of fusing together each of the following near the base end of the first shaft: the first shaft forming a guidewire lumen and a guidewire port located at the base end of the guidewire lumen; the second shaft communicating with the lumen of the balloon and having a portion of the inflation lumen along the guidewire lumen; and the third shaft having a portion of the inflation lumen extending at least along the base end of the second shaft; and prior to the fusion step, the method comprising inserting a first core through the guidewire lumen of the first shaft, and inserting a second core through the inflation lumen of the second shaft and the inflation lumen of the third shaft. A method for manufacturing a balloon catheter, comprising: a step of arranging a first heat-shrinkable tube so as to cover the fusion points of the first shaft, the second shaft, and the third shaft before the fusion step; and an arrangement step of arranging a second heat-shrinkable tube so as to cover the first heat-shrinkable tube, wherein in the arrangement step, the second heat-shrinkable tube is arranged in a range of 4 mm or less from the base end to the tip side of the first shaft; and in the fusion step, heat is applied to the first heat-shrinkable tube and the second heat-shrinkable tube to shrink their diameters and fuse the first shaft, the second shaft, and the third shaft together.

7. The method for manufacturing a balloon catheter according to claim 6, wherein in the arrangement step, the first heat shrink tube is arranged to extend longer toward the tip than the second heat shrink tube.

8. A heat shrinkable tube used in the manufacture of a balloon catheter comprising a shaft portion having a first shaft, a second shaft, and a third shaft, and a balloon disposed at the tip of the shaft portion, wherein the heat shrinkable tube is used when each of the first shaft having a guidewire lumen and a guidewire port located at the proximal end of the guidewire lumen, the second shaft communicating with the lumen of the balloon and having a portion of the inflation lumen along the guidewire lumen, and the third shaft having a portion of the inflation lumen extending at least along the proximal end of the second shaft, is fused together near the proximal end of the first shaft, and the length along the axial direction of the shaft portion is 4 mm.

9. The heat shrinkable tube according to claim 8, wherein the heat shrinkable tube is made of silicone having a thickness of 0.2 mm or more and 0.45 mm or less after heat shrinkage.

10. The heat shrinkable tube according to claim 8 or claim 9, wherein the heat shrinkable tube has a shrinkage rate of 50% before and after heating.

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