Medical device and method for producing medical device

Abstract

This medical device comprises: a first proximal-end-side tube which has a first flexural rigidity and which constitutes part of a first lumen; a first distal-end-side tube which has a second flexural rigidity lower than the first flexural rigidity, which is disposed further to the distal end side than the first proximal-end-side tube, a proximal end part of which is joined to a distal end part of the first proximal-end-side tube, and which constitutes part of the first lumen; a second proximal-end-side tube which has a third flexural rigidity and which constitutes part of a second lumen; and a second distal-end-side tube which has a fourth flexural rigidity lower than the third flexural rigidity, which is disposed further to the distal end side than the second proximal-end-side tube, a proximal end part of which is joined to a distal end part of the second proximal-end-side tube, and which constitutes part of the second lumen, the distal end position of the second proximal-end-side tube being further to the distal end side than the distal end position of the first proximal-end-side tube in the length direction of the medical device.

Description

Medical device and method for manufacturing medical device

[0001] The present invention relates to medical devices and methods for manufacturing medical devices.

[0002] Catheters used in percutaneous procedures are known. To enable safe and efficient implementation of complex percutaneous procedures, the procedures may be performed under the guidance of a sensor that acquires image information of biological tissue using ultrasound. In such cases, a catheter with two lumens is used, with the sensor inserted into one lumen and a treatment device inserted into the other lumen, allowing the procedure to be performed using both the sensor and the treatment device. To improve safety and operability, such catheters generally have a thin, flexible distal end and a thick, rigid proximal end.

[0003] For example, Patent Document 1 discloses a device including a support tube having a distal portion made only of flexible resin and a proximal portion in which an inner resin layer and an outer resin layer are integrally laminated.For example, Patent Document 2 discloses a medical elongated member including a first member and a second member having an inner diameter larger than that of the first member and disposed on the proximal side of the first member, the proximal end of the first member and the distal end of the second member being connected by connecting members.

[0004] JP 2007-082707 A JP 2015-062532 A

[0005] However, the device described in Patent Document 1 has a problem in that it does not take into consideration the rigidity gap at the boundary between the flexible distal end portion and the highly rigid proximal end portion. Furthermore, the elongated member described in Patent Document 2 has only a single lumen and is used only for treatment within the pulmonary airways, and does not take into consideration a multi-lumen configuration for implementing procedures under sensor guidance. These problems are not limited to the vascular system, but are common to medical devices inserted into various organs within the human body, such as the lymphatic system, biliary system, urinary system, respiratory system, digestive system, secretory glands, and reproductive organs.

[0006] The present invention has been made to solve at least some of the above-mentioned problems, and aims to achieve gradual change in stiffness in a medical device having at least two or more lumens formed by different tubes arranged on the distal and proximal ends.

[0007] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized in the following aspects.

[0008] (1) According to one aspect of the present invention, there is provided a medical device comprising: a first proximal tube having a first bending stiffness and constituting a part of a first lumen; a first distal tube having a second bending stiffness lower than the first bending stiffness, disposed distal to the first proximal tube, joined at its proximal end to a distal end of the first proximal tube, and constituting a part of the first lumen; a second proximal tube having a third bending stiffness and constituting a part of the second lumen; and a second distal tube having a fourth bending stiffness lower than the third bending stiffness, disposed distal to the second proximal tube, joined at its proximal end to a distal end of the second proximal tube, and constituting a part of the second lumen, the distal position of the second proximal tube being located distal to a distal position of the first proximal tube in the longitudinal direction of the medical device.

[0009] According to this configuration, the distal end of the second proximal tube is located distally of the distal end of the first proximal tube. That is, the first joint where the first distal tube and the first proximal tube are joined and the second joint where the second distal tube and the second proximal tube are joined are offset (located at different positions) in the longitudinal direction of the medical device. This allows for a gradual change in the rigidity of the medical device compared to when the first joint and the second joint are located at the same position, thereby preventing kinking of the medical device. As a result, buckling of the medical device when a pushing force is applied to the medical device during use can be prevented.

[0010] (2) In the medical device of the above aspect, the distal end of the first proximal tube may be provided with a tapered portion whose outer diameter narrows from the proximal end toward the distal end, and the outer circumferential surface of the tapered portion may be in contact with the inner circumferential surface of the first distal tube. With this configuration, the tapered portion makes it easy to connect the first proximal tube to the first distal tube.

[0011] (3) The medical device of the above aspect may further include a third tube that defines a third lumen and has its proximal end located between the distal end and the proximal end of the tapered portion. With this configuration, the medical device can be configured to have a third lumen.

[0012] (4) In the medical device of the above aspect, the first proximal tube and the second proximal tube may be bundled together by a heat-shrinkable tube, and the heat-shrinkable tube may be disposed between the distal end and the proximal end of the tapered portion. According to this configuration, the first proximal tube and the second proximal tube can be bundled together without adhesive by using the heat-shrinkable tube. Furthermore, because the heat-shrinkable tube is disposed between the distal end and the proximal end of the tapered portion, the presence of the heat-shrinkable tube can prevent the outer diameter of the medical device from increasing.

[0013] (5) In the medical device of the above aspect, the tapered portion may be a first tapered portion, and the distal end of the second proximal tube may be provided with a second tapered portion whose outer diameter narrows from the proximal end to the distal end, the outer circumferential surface of the second tapered portion contacting the inner circumferential surface of the second distal tube, and the length of the first tapered portion in the longitudinal direction of the medical device may be longer than the length of the second tapered portion. According to this configuration, the second tapered portion makes it easier to connect the second proximal tube to the second distal tube. Furthermore, by making the lengths of the first tapered portion and the second tapered portion different, the gradual change in rigidity can be further improved.

[0014] (6) In the medical device of the above aspect, the outer diameter of the first proximal tube may be larger than the outer diameter of the second proximal tube, and the proximal position of the second tapered section may be located distal to the distal position of the first proximal tube in the longitudinal direction of the medical device. This configuration reduces the variation in the outer diameters of the first proximal tube and the second proximal tube in a longitudinal section of the medical device where three tubes (specifically, the first proximal tube, the second proximal tube, and the third tube) are present. As a result, the positional deviation of the third tube can be reduced.

[0015] (7) In the medical device of the above aspect, the melting point of the first proximal tube may be higher than the melting point of the first distal tube. With this configuration, tubes with different melting points can be joined together.

[0016] (8) In the medical device of the above aspect, the first proximal tube and the first distal tube may be in contact with each other in an incompatible state. With this configuration, the tubes can be joined without causing the tubes to be incompatible with each other.

[0017] (9) In the medical device of the above aspect, the outer diameter of the first base-side tube may be larger than the outer diameter of the second base-side tube.

[0018] (10) According to one aspect of the present invention, there is provided a method for manufacturing a medical device. The method includes stretching a first proximal tube to form a constriction in the first proximal tube, cutting the first proximal tube at the constriction to form a tapered portion at a distal end of the first proximal tube, and inserting at least a portion of the tapered portion of the first proximal tube into a first distal tube. This manufacturing method allows the first proximal tube and the first distal tube to be joined together using the tapered portion formed at the distal end of the first proximal tube.

[0019] (11) In the method for manufacturing a medical device according to the above aspect, when the first proximal tube is stretched, the first proximal tube may be heated to a temperature that is 100° C. or more higher than the melting point of the first distal tube. According to this manufacturing method, the first proximal tube and the first distal tube can be joined even if the melting points of the first proximal tube and the first distal tube differ by 100° C. or more.

[0020] (12) In the method for manufacturing a medical device according to the above aspect, before the insertion, the outer diameter of the first distal tube at the proximal end may be substantially the same as the outer diameter at a predetermined position longitudinally spaced from the proximal end of the first distal tube, and before the insertion, the inner diameter of the first distal tube at the proximal end may be substantially the same as the inner diameter at the predetermined position. This manufacturing method allows the first proximal tube and the first distal tube to be joined without processing (e.g., flaring) the first distal tube.

[0021] The present invention can be realized in various aspects, for example, in the form of a medical device, a medical tube, a catheter, and a method for manufacturing these.

[0022] FIG. 1 is an explanatory diagram illustrating the configuration of a medical device. FIG. 1 is an explanatory diagram illustrating the configuration of a medical device. FIG. 2 is a cross-sectional view of a catheter. FIG. 3 is a diagram illustrating a method of using a catheter. FIG. 4 is a diagram illustrating a method of using a catheter. FIG. 5 is an enlarged view of the vicinity of a tube junction in a catheter. FIG. 6 is a cross-sectional view of a catheter. FIG. 7 is a diagram illustrating a method of manufacturing a catheter. FIG. 8 is a diagram illustrating a method of manufacturing a catheter of a second embodiment. FIG. 9 is an enlarged view of the vicinity of a tube junction in a catheter of a third embodiment. FIG. 10 is a diagram illustrating a method of manufacturing a catheter of a fourth embodiment. FIG. 11 is an enlarged view of the vicinity of a tube junction in a catheter of a fifth embodiment.

[0023] 1 and 2 are explanatory diagrams illustrating an example of the configuration of a medical device 1. The medical device 1 of this embodiment is a catheter. Hereinafter, the medical device 1 will also be referred to as a "catheter 1." The catheter 1 is used to treat a lesion in a biological lumen, such as a CTO (Cardiac Tissue Occurring in a blood vessel). As shown in FIGS. 1 and 2, the catheter 1 includes a sensor tube 10, an over-the-wire (OTW) tube 20, a rapid exchange (RX) tube 30, a distal tip 40, a first marker 41, a second marker 42, a first outer tube 50, a branched connector 60, first to third reinforcing members 61 to 63, a tubular member 64, a connector 65, a connector 25, a sensor 70, a second outer tube 80, and a heat-shrinkable tube 90. The sensor tube 10 is also referred to as a "medical device" or a "medical tube." The OTW tube 20 is also called a "medical device" or "medical tube."

[0024] In order to explain the configuration of the tube and the lumen within the tube, the sensor 70 is not shown in Fig. 1. In Fig. 2, the sensor 70 built into the sensor lumen 10L within the sensor tube 10 is indicated by a dashed line and hatched with diagonal lines.

[0025] For ease of explanation, Figures 1 and 2 include portions in which the relative size ratios of the components are different from the actual ratios. Also, some of the components are exaggerated. Also, Figures 1 and 2 illustrate mutually orthogonal X, Y, and Z axes. The X axis corresponds to the longitudinal direction of the catheter 1, the Y axis corresponds to the height direction of the catheter 1, and the Z axis corresponds to the width direction of the catheter 1. The left side (-X axis direction) of Figures 1 and 2 is referred to as the "distal side" of the catheter 1 and each component, and the right side (+X axis direction) of Figures 1 and 2 is referred to as the "proximal side" of the catheter 1 and each component. Of the two ends of the catheter 1 and each component in the longitudinal direction (X axis direction), the one end located on the distal side is referred to as the "distal end," and the other end located on the proximal side is referred to as the "proximal end." The distal end and its vicinity are referred to as the "distal portion," and the proximal end and its vicinity are referred to as the "proximal end." The distal end is inserted into the living body, and the proximal end is operated by an operator such as a physician. These points are also common to FIG. 3 and subsequent figures.

[0026] FIG. 3 is a cross-sectional view of the catheter 1. FIG. 3(A) shows a cross-section of the catheter 1 taken along line A-A in FIG. 1. FIG. 3(B) shows a cross-section of the catheter 1 taken along line B-B in FIG. 1. FIG. 3(C) shows a cross-section of the catheter 1 taken along line C-C in FIG. 1. FIG. 3(D) shows a cross-section of the catheter 1 taken along line D-D in FIG. 1. FIG. 3(E) shows a cross-section of the catheter 1 taken along line E-E in FIG. 1. The configuration of the catheter 1 will be described below with reference to FIGS. 1 to 3.

[0027] The sensor tube 10 is a cylindrical member (tubular body) having an elongated outer shape. The sensor tube 10 extends linearly along the longitudinal direction (X-axis direction) of the catheter 1, parallel to the OTW tube 20 and the RX tube 30. A sensor lumen 10L (dashed line) for accommodating the sensor 70 is formed inside the sensor tube 10. The sensor lumen 10L is a lumen for the sensor 70.

[0028] The distal end of the sensor tube 10 is located at the same position as or slightly closer to the proximal end than the distal end of the RX tube 30 in the longitudinal direction of the catheter 1. A distal opening 101 is formed at the distal end of the sensor tube 10, connecting the distal end of the sensor lumen 10L to the outside. The distal opening 101 is a fluid outlet for maintaining a wet state inside the sensor lumen 10L. The proximal end of the sensor tube 10 is located closer to the proximal end than the proximal end of the OTW lumen 20L and the proximal end of the RX tube 30 in the longitudinal direction of the catheter 1. A first reinforcing member 61, a branch connector 60, a tubular member 64, and a connector 65 are attached to the proximal end of the sensor tube 10, from the distal end toward the proximal end. Details will be described later. A fluid supply unit 66 is attached to the connector 65, and a proximal opening 102 is formed in the fluid supply unit 66, connecting the proximal end of the sensor lumen 10L to the outside. The proximal opening 102 is a fluid supply port to the sensor lumen 10L.

[0029] 1 , the sensor tube 10 includes a first distal tube 11 disposed on the distal side and a first proximal tube 12 disposed on the proximal side of the first distal tube 11. The first distal tube 11 and the first proximal tube 12 are both cylindrical members (tubular bodies) having elongated outer shapes. The first distal tube 11 and the first proximal tube 12 are connected to each other inside the first outer tube 50 in the longitudinal direction. That is, the first distal tube 11 and the first proximal tube 12 each constitute a part of the sensor lumen 10L.

[0030] The OTW tube 20 is a cylindrical member (tubular body) having a long outer shape. The OTW tube 20 extends linearly along the longitudinal direction of the catheter 1, parallel to the sensor tube 10 and the RX tube 30, distal to the branch connector 60. An OTW lumen 20L (shown by a broken line) is formed inside the OTW tube 20 for accommodating a treatment device (e.g., a plasma guidewire or a penetration guidewire). The OTW lumen 20L does not have a proximal opening in the portion that is placed inside the biological lumen when the catheter 1 is in use. The OTW lumen 20L is an over-the-wire (OTW) type lumen.

[0031] The distal end of the OTW tube 20 is located closer to the proximal end than the distal end of the sensor tube 10 and the distal end of the RX tube 30 in the longitudinal direction of the catheter 1. A distal opening 201 that connects the distal end of the OTW lumen 20L to the outside is formed at the distal end of the OTW tube 20. The distal opening 201 is a device ejection port for ejecting a therapeutic device toward biological tissue. By cutting the distal end of the OTW tube 20 obliquely, the distal opening 201 faces in a direction intersecting the longitudinal direction of the catheter 1. This makes it easier for the therapeutic device to reach biological tissue present around the catheter 1 when the catheter 1 is in use. The proximal end of the OTW tube 20 is located closer to the distal end of the sensor tube 10 and closer to the proximal end of the RX tube 30 in the longitudinal direction of the catheter 1. On the proximal end side of the OTW tube 20, a first reinforcing member 61, a branch connector 60, a second reinforcing member 62, a third reinforcing member 63, and a connector 25 are attached, from the distal end side to the proximal end side. Details will be described later. The connector 25 has a proximal end opening 202 that connects the proximal end of the OTW lumen 20L to the outside. The proximal end opening 202 is a device insertion port for inserting a therapeutic device into the OTW lumen 20L.

[0032] 1 , the OTW tube 20 includes a second distal tube 21 disposed on the distal side and a second proximal tube 22 disposed on the proximal side of the second distal tube 21. The second distal tube 21 and the second proximal tube 22 are both cylindrical members (tubular bodies) having an elongated outer shape. The second distal tube 21 and the second proximal tube 22 are connected to each other inside the first outer tube 50 in the longitudinal direction. That is, the second distal tube 21 and the second proximal tube 22 each constitute a part of the OTW lumen 20L.

[0033] The RX tube 30 is a cylindrical member (tubular body) having an elongated outer shape. The RX tube 30 extends linearly along the longitudinal direction of the catheter 1, parallel to the sensor tube 10 and the OTW tube 20. An RX lumen 30L (dashed line) for accommodating a work hose wire is formed inside the RX tube 30.

[0034] The distal end of the RX tube 30 is located at the same position as or slightly distal to the distal end of the sensor tube 10 in the longitudinal direction of the catheter 1. A hollow distal tip 40 is joined to the distal portion of the RX tube 30. A distal opening 301 is formed at the distal end of the distal tip 40, connecting the distal end of the RX lumen 30L to the outside. The distal opening 301 is a wire insertion port for inserting the work horse wire into the RX lumen 30L. The proximal end of the RX tube 30 is located distal to the proximal end of the sensor tube 10 and the proximal end of the OTW tube 20 in the longitudinal direction of the catheter 1. A proximal end opening 302 is formed at the proximal end of the RX tube 30, connecting the proximal end of the RX lumen 30L to the outside. The proximal end opening 302 is a wire withdrawal port for withdrawing the work horse wire to the outside. By cutting the base end of the RX tube 30 obliquely, the base end opening 302 faces in a direction intersecting the longitudinal direction of the catheter 1. This makes it easier to pull out the work hose wire from the base end opening 302 when the catheter 1 is in use.

[0035] The distal tip 40 is a radiopaque, tubular member whose outer diameter expands from the distal end to the proximal end. The distal tip 40 is positioned at the distal end of the catheter 1 by being joined to the distal portion of the RX tube 30, and advances through the biological lumen ahead of other members. The lumen of the distal tip 40 communicates with the RX lumen 30L of the RX tube 30, and as described above, a distal opening 301 is formed at the distal end of the distal tip 40, which communicates the distal end of the RX lumen 30L with the outside.

[0036] The first marker 41 and the second marker 42 are annular radiopaque members. The first marker 41 is arranged so that the base end of the first marker 41 and the base end of the distal tip 40 are aligned in the longitudinal direction of the catheter 1. The first marker 41 is embedded between the outer circumferential surface of the RX tube 30 and the inner circumferential surface of the distal tip 40. The second marker 42 is arranged so that the base end of the second marker 42 and the distal tip opening 201 are aligned in the longitudinal direction of the catheter 1. The second marker 42 is bonded to the outer circumferential surface of the RX tube 30. The first marker 41 and the second marker 42 can be bonded, for example, by thermally fusing resins or by using an adhesive such as an epoxy adhesive. The second marker 42 may be colored so that it can be directly viewed by the surgeon. In this way, by placing the first marker 41 and the second marker 42 on the RX tube 30, it is possible to prevent the first marker 41 and the second marker 42 from interfering with sensing (acquisition of image information) by the sensor 70.

[0037] As shown in Fig. 3A, in the cross section taken along line A-A, the sensor tube 10 (specifically, the first distal tube 11) and the RX tube 30 are arranged, with their outer peripheral surfaces joined together. As shown in Fig. 3B, in the cross section taken along line B-B, the sensor tube 10 (specifically, the first distal tube 11), the OTW tube 20 (specifically, the second distal tube 21), and the RX tube 30 are arranged, with their outer peripheral surfaces joined together. As shown in Fig. 3C, in the cross section taken along line C-C, the sensor tube 10 (specifically, the first distal tube 11), the OTW tube 20 (specifically, the second distal tube 21), and the RX tube 30 are covered by the first outer tube 50. Specifically, the outer circumferential surfaces of the three tubes 10, 20, and 30 are covered with a melt-formed first outer tube 50, thereby fixing the three tubes 10, 20, and 30 together. As shown in FIG. 3(D) , in a cross section taken along line D-D, the sensor tube 10 (specifically, the first distal tube 11), the OTW tube 20 (specifically, the second proximal tube 22), and the RX tube 30 are covered with the first outer tube 50, as in FIG. 3(C) . As shown in FIG. 3(E) , in a cross section taken along line E-E, the sensor tube 10 (specifically, the first proximal tube 12) and the OTW tube 20 (specifically, the second proximal tube 22) are covered with a second outer tube 80. Specifically, the outer circumferential surfaces of the two tubes 10 and 20 are covered with a melt-formed second outer tube 80, thereby fixing the two tubes 10 and 20 together.

[0038] The sensor tube 10, the OTW tube 20, and the RX tube 30 may be joined in the A-A cross section and the B-B cross section using any bonding agent such as an epoxy adhesive, or may be thermally welded. In the A-A cross section, the B-B cross section, the C-C cross section, and the D-D cross section, the height LY of the catheter 1 is greater than the width LZ of the catheter 1. On the other hand, in the E-E cross section, the height LY of the catheter 1 is smaller than the width LZ of the catheter 1. As shown in FIGS. 3A to 3E , the relationship between the outer diameters of the three tubes 10, 20, and 30 is: outer diameter of the sensor tube 10 > outer diameter of the OTW tube 20 > outer diameter of the RX tube 30. Furthermore, the relationship between the inner diameters (lumens) of the three tubes 10, 20, and 30 is: inner diameter of the sensor lumen 10L > inner diameter of the OTW lumen 20L > inner diameter of the RX lumen 30L. However, this relationship between the outer diameter and the inner diameter is merely an example and may be changed as desired.

[0039] The A-A cross section and the B-B cross section, in other words, the outer shape of the catheter 1 distal to the first outer tube 50, is a shape that follows the contours of the two tubes 10, 30 (or the three tubes 10, 20, 30) arranged adjacent to each other, with a constriction (recess) formed in the adjacent portion of each tube. The C-C cross section and the D-D cross section, in other words, the outer shape of the catheter 1 in the portion covered by the first outer tube 50, is a triangle with rounded corners (rounded-corner triangle). The E-E cross section, in other words, the outer shape of the catheter 1 in the portion covered by the second outer tube 80, is an ellipse.

[0040] 1, the three tubes 10, 20, and 30 (specifically, the sensor tube 10, the OTW tube 20, and the RX tube 30) are fixed by three tubes 90, 50, and 80.

[0041] The heat-shrinkable tube 90 is disposed between the first outer tube 50 and the second outer tube 80 in the longitudinal direction of the catheter 1. The heat-shrinkable tube 90 covers the sensor tube 10 (specifically, a portion of the distal end of the first proximal tube 12) and the OTW tube 20 (specifically, a portion of the distal end of the second proximal tube 22) to bundle the two tubes 10, 20. The heat-shrinkable tube 90 does not cover the RX tube 30, which is disposed along the outer circumferential surface of the heat-shrinkable tube 90 with the outer circumferential surface of the heat-shrinkable tube 90 in contact with the outer circumferential surface of the RX tube 30. The distal end of the heat-shrinkable tube 90 is located closer to the proximal end than the distal end of the first outer tube 50 and closer to the distal end than the proximal opening 302. In other words, the distal end of the heat-shrinkable tube 90 is covered by the first outer tube 50. The base end of the heat-shrinkable tube 90 is located closer to the base end than the tip of the second outer tube 80 and closer to the tip end than the first reinforcing member 61. That is, the base end of the heat-shrinkable tube 90 is covered by the second outer tube 80. In other words, the intermediate portion of the heat-shrinkable tube 90 in the longitudinal direction of the catheter 1 is not covered by the first outer tube 50 or the second outer tube 80.

[0042] The first outer tube 50 is disposed distally of the heat-shrinkable tube 90 in the longitudinal direction of the catheter 1. The first outer tube 50 is disposed proximal to the distal opening 201, in a section where the three tubes 10, 20, and 30 extend side by side. In the example shown in FIG. 1 , the distal end of the first outer tube 50 is located near the center between the distal opening 201 and the proximal opening 302. The proximal end of the first outer tube 50 is located near the proximal end of the proximal opening 302. In this manner, the first outer tube 50 is preferably disposed at a position away from the distal opening 201 toward the proximal end. This prevents the first outer tube 50 from interfering with sensing (acquisition of image information) by the sensor 70 inserted in the sensor lumen 10L. The first outer tube 50 covers and fixes the distal end of the heat shrink tube 90, the sensor tube 10 exposed from the distal end of the heat shrink tube 90 (specifically, a proximal portion of the first distal tube 11), the OTW tube 20 exposed from the distal end of the heat shrink tube 90 (specifically, a proximal portion of the second distal tube 21 and a distal portion of the second proximal tube 22), and the RX tube 30. As shown in Figures 3(C) and 3(D) , the first outer tube 50 has an outer shape like a rounded triangle, and has thick-walled portions melt-molded along the outer peripheral surfaces of the three tubes 10, 20, and 30.

[0043] The second outer tube 80 is disposed closer to the proximal end than the heat-shrink tube 90 in the longitudinal direction of the catheter 1. The second outer tube 80 is disposed closer to the proximal end than the proximal opening 302, in a section where the two tubes 10, 20 extend side by side. In the example of FIG. 1 , the distal end of the second outer tube 80 is located slightly proximally away from the proximal opening 302. The proximal end of the second outer tube 80 is located inside the first reinforcing member 61. The second outer tube 80 covers and fixes the proximal end of the heat-shrink tube 90, the sensor tube 10 exposed from the proximal end of the heat-shrink tube 90 (specifically, a proximal portion of the first proximal tube 12), and the OTW tube 20 exposed from the proximal end of the heat-shrink tube 90 (specifically, a portion of the second proximal tube 22). As shown in FIG. 3(E), the second outer tube 80 has an elliptical outer shape and has a thick-walled portion that is melt-molded along the outer circumferential surfaces of the two tubes 10, 20.

[0044] The branch connector 60 is a member having a bifurcated lumen and is disposed on the proximal end side of the catheter 1. The OTW tube 20 is inserted into one lumen of the branch connector 60. The sensor tube 10 is inserted into the other lumen of the branch connector 60. The first reinforcing member 61 is a cylindrical member disposed on the distal side of the branch connector 60. The first reinforcing member 61 reinforces the distal side of the branch connector 60 by covering the outer periphery of the second outer tube 80 that bundles the sensor tube 10 and the OTW tube 20.

[0045] The second reinforcing member 62 is a cylindrical member located closer to the proximal end than one branch of the branch connector 60. The second reinforcing member 62 reinforces the proximal end of the branch connector 60 by covering the outer periphery of the OTW tube 20 inserted into the branch connector 60. The third reinforcing member 63 is a cylindrical member located closer to the distal end than the connector 25. The third reinforcing member 63 reinforces the distal end of the connector 25 by covering the outer periphery of the OTW tube 20 inserted into the connector 25. The connector 25 is a member joined to the proximal end of the OTW tube 20. The connector 25 has a pair of wings for gripping by the surgeon. A proximal end opening 202 (device insertion port) that connects the proximal end of the OTW lumen 20L to the outside is formed at the proximal end of the connector 25.

[0046] The tubular member 64 is a cylindrical member located closer to the base end than the other branch of the branch connector 60. The tubular member 64 reinforces the base end of the branch connector 60 by covering the outer periphery of the sensor tube 10 inserted into the branch connector 60. The connector 65 is a member joined to the base end of the sensor tube 10. A housing for accommodating the connection terminal 75 of the sensor 70 is provided on the base end side of the connector 65. A fluid supply section 66 is provided on the outer periphery of the connector 65, and the fluid supply section 66 has a base end opening 102 formed therein, which communicates the base end of the sensor lumen 10L with the outside.

[0047] The sensor 70 ( FIG. 2 ) is an imaging sensor for acquiring image information. As shown in FIG. 2 , the sensor 70 includes a main body 71, a probe 72, and a connection terminal 75. The main body 71 is an elongated member extending along the longitudinal direction of the catheter 1. A driving cable (coaxial cable) is built into the main body 71, electrically connecting the probe 72 and the connection terminal 75. The probe 72 includes an ultrasound probe (also called an ultrasound vibrator, piezoelectric element, ultrasound transmitting / receiving element, or ultrasound element) that transmits ultrasound toward biological tissue and receives ultrasound reflected from the biological tissue. The probe 72 is also called an imaging core or transducer. The connection terminal 75 electrically connects the sensor 70 to an external console terminal. The connection terminal 75 is provided at the base end of the main body 71 and is housed within the housing of the connector 65.

[0048] The sensor 70 is electrically connected to an external console terminal via a connection terminal 75, receives power from the console terminal, and outputs a detection signal from the probe 72 to the console terminal. This allows the console terminal to display image information based on the detection signal from the probe 72. As shown in FIG. 2 , the sensor 70 is fixed to a connector 65. As indicated by the white arrow in FIG. 2 , the surgeon grasps the connector 65 and slides it back and forth (in the direction of the white arrow) to move the position of the probe 72 of the sensor 70 within a range MR from the tip of the sensor lumen 10L to the tip of the first outer tube 50—in other words, within a predetermined range MR including the distal end opening 201. Hereinafter, this range MR will also be referred to as the “movable range MR.” Furthermore, a portion of the catheter 1 that is particularly suitable for sensing (acquisition of image information) by the sensor 70 will also be referred to as the “acoustic window AW.” As shown in FIG. 2 , the acoustic window AW is the section of the catheter 1 between the first marker 41 and the second marker 42.

[0049] The first distal tube 11 of the sensor tube 10, the second distal tube 21 of the OTW tube 20, and the RX tube 30 can be made of flexible materials such as thermoplastic resins such as polyethylene resin, polypropylene resin, and polyurethane, polyvinyl chloride, ethylene-vinyl acetate copolymer, cross-linked ethylene-vinyl acetate copolymer, polyamide elastomer, polyolefin elastomer, polyurethane elastomer, silicone rubber, and latex rubber. The first distal tube 11 of the sensor tube 10, the second distal tube 21 of the OTW tube 20, and the RX tube 30 may be made of the same material or different materials.

[0050] The first proximal tube 12 of the sensor tube 10 and the second proximal tube 22 of the OTW tube 20 can be made of a highly rigid resin such as nylon resin, polyester resin, or PEEK resin. The melting points of the first proximal tube 12 of the sensor tube 10 and the second proximal tube 22 of the OTW tube 20 are higher than the melting points of the above-mentioned tubes 11, 21, and 30. The first proximal tube 12 of the sensor tube 10 and the second proximal tube 22 of the OTW tube 20 may be made of the same material or different materials.

[0051] In the catheter 1 of this embodiment, a section is provided in which a proximal portion of the flexible RX tube 30 overlaps with the highly rigid first proximal tube 12 and second proximal tube 22 (FIG. 1), thereby achieving a gradual change in the rigidity of the catheter 1 (reducing the rigidity gap of the catheter 1). This makes it possible to suppress kinking of the catheter 1. Note that one or more of the first distal tube 11 and first proximal tube 12 of the sensor tube 10, the second distal tube 21 and second proximal tube 22 of the OTW tube 20, and the RX tube 30 may have a multi-layer structure in which tubes made of different materials are overlapped.

[0052] The distal tip 40, the first marker 41, and the second marker 42 can be formed from a radiopaque resin or metal material. For example, when a radiopaque resin material is used, it can be formed by mixing a radiopaque material such as bismuth trioxide, tungsten, or barium sulfate with a polyamide resin, polyolefin resin, polyester resin, polyurethane resin, silicone resin, or fluororesin. For example, when a radiopaque metal material is used, it can be formed from gold, platinum, tungsten, or an alloy containing these elements (e.g., platinum-nickel alloy). The distal tip 40, the first marker 41, and the second marker 42 can be formed from the same material or different materials.

[0053] The branch connector 60, the first reinforcing member 61 to the third reinforcing member 63, the tubular member 64, the connector 65, and the connector 25 can be made of a known resin material. The branch connector 60, the first reinforcing member 61 to the third reinforcing member 63, the tubular member 64, the connector 65, and the connector 25 may be made of the same material or different materials.

[0054] The heat-shrinkable tube 90 is made of a thermoplastic nylon-based elastomer resin (e.g., polyamide elastomer). The heat-shrinkable tube 90 has the property of shrinking without melting when heated. Furthermore, the heat-shrinkable tube 90 has improved adhesiveness (the ability to easily stick to other substances) when heated compared to when not heated. The heat-shrinkable tube 90 may also be made of polyolefin, FEP (Fluorinated Ethylene Propylene), or silicone.

[0055] The first outer tube 50 and the second outer tube 80 are made of a nylon-based elastomer resin having thermoplastic properties. Unlike the heat-shrinkable tube 90, the first outer tube 50 and the second outer tube 80 have the property of melting when heated. In this embodiment, the first outer tube 50 uses a resin having a lower Shore hardness than the second outer tube 80. However, the first outer tube 50 and the second outer tube 80 may be made of the same material or different materials.

[0056] 4 and 5 are diagrams illustrating a method of using the catheter 1. Steps a1 to a6 shown below illustrate an example of attempting to recanalize a CTO (lesion) that has occurred in a blood vessel using an antegrade approach. However, the catheter 1 may also be used in a retrograde approach, or for procedures other than CTO recanalization.

[0057] (a1) The surgeon inserts the workhorse wire 200 into a blood vessel and delivers the distal end of the workhorse wire 200 to the vicinity of the CTO. (a2) The surgeon inserts the proximal end of the workhorse wire 200 from the distal opening 301 of the catheter 1, passes it through the RX lumen 30L, and pulls it out from the proximal opening 302 of the catheter 1 ( FIG. 4 ). (a3) ​​The surgeon pushes the catheter 1 along the workhorse wire 200 into the blood vessel and delivers the distal end of the catheter 1 to the vicinity of the CTO. Note that in step a3, the catheter 1 may be delivered to the vicinity of the CTO by passing it through a guiding catheter that has been inserted into the blood vessel in advance along the workhorse wire 200. (a4) The surgeon grasps the connector 65 and slides it back and forth (in the direction of the white arrow in Figure 5 ) to adjust the position of the probe 72 of the sensor 70 within the movable range MR, while checking the image displayed on the console terminal to align the position and orientation of the CTO and the distal opening 201. The term "position" refers to the position in the extension direction of the blood vessel, and the term "orientation" refers to the orientation in the circumferential direction of the inner wall of the blood vessel. (a5) The surgeon inserts the distal end of the treatment device 300 through the proximal opening 202 of the catheter 1, passes it through the OTW lumen 20L, and protrudes it from the distal opening 201 of the catheter 1 ( Figure 5 ). (a6) The surgeon treats the CTO using the treatment device 300 while adjusting the position of the probe 72 of the sensor 70 within the movable range MR as needed and checking the image displayed on the console terminal. As described above, any device, such as a plasma guidewire or a penetration guidewire, can be used as the treatment device 300.

[0058] The sensor tube 10, the OTW tube 20, and the RX tube 30 are also collectively referred to as the "shaft." The sensor tube 10 corresponds to the "first tube," and the sensor lumen 10L corresponds to the "first lumen." The OTW tube 20 corresponds to the "second tube," and the OTW lumen 20L corresponds to the "second lumen." The RX tube 30 corresponds to the "third tube," and the RX lumen 30L corresponds to the "third lumen." The heat shrink tube 90 corresponds to the "heat shrink tube." In this embodiment, "same" and "equal" do not necessarily mean exact agreement, but also mean allowing for differences due to manufacturing errors, etc. Furthermore, "constant" is synonymous with "approximately constant," meaning approximately constant while allowing for variations due to manufacturing errors, etc.

[0059] Figure 6 is an enlarged view of the vicinity of the tube joint portion of the catheter 1. For ease of explanation, the first proximal tube 12 and the second proximal tube 22 are shown with diagonal hatching in Figure 6. Figure 7 is a transverse cross-sectional view of the catheter 1. Figure 7(A) shows a transverse cross-section taken along line F-F in Figure 6. Figure 7(B) shows a transverse cross-section taken along line G-G in Figure 6. The joint between the first and second distal tubes 11, 21 and the first and second proximal tubes 12, 22 will be further described using Figures 6 and 7.

[0060] In the sensor tube 10, the bending rigidity of the first proximal tube 12 is referred to as the "first bending rigidity," and the bending rigidity of the first distal tube 11 is referred to as the "second bending rigidity." Here, the second bending rigidity is lower than the first bending rigidity. Therefore, the melting point of the first proximal tube 12 is higher than the melting point of the first distal tube 11. In the OTW tube 20, the bending rigidity of the second proximal tube 22 is referred to as the "third bending rigidity," and the bending rigidity of the second distal tube 21 is referred to as the "fourth bending rigidity." Here, the fourth bending rigidity is lower than the third bending rigidity. Therefore, the melting point of the second proximal tube 22 is higher than the melting point of the second distal tube 21. The first to fourth bending rigidities can be determined arbitrarily as long as they satisfy the above-described magnitude relationship. In the example of this embodiment, the first bending rigidity and the third bending rigidity are the same, but they may be different. Furthermore, although the second bending stiffness and the fourth bending stiffness are the same, they may be different.

[0061] The first distal tube 11 of the sensor tube 10 is positioned distally of the first proximal tube 12, and the distal end of the first proximal tube 12 is joined to the proximal end of the first distal tube 11. This configuration forms the sensor tube 10 having a sensor lumen 10L. The distal end of the first proximal tube 12 is provided with a first tapered section 121, in which the outer diameter of the first proximal tube 12 narrows from the proximal end toward the distal end. In the first tapered section 121, the wall thickness of the first proximal tube 12 gradually decreases toward the distal end. The first tapered section 121 is covered by the proximal end of the first distal tube 11. In other words, the first distal tube 11 and the first proximal tube 12 overlap within the range of the first tapered section 121. The first tapered section 121 is also referred to simply as the "tapered section."

[0062] The first distal tube 11 and the first proximal tube 12 are joined in an incompatible state at the overlapping portion of the first distal tube 11 and the first proximal tube 12. Hereinafter, this portion will also be referred to as the "first joint portion." As shown in FIG. 7A , at the first joint portion, the outer peripheral surface 121o of the first tapered portion 121 contacts the inner peripheral surface 11i of the first distal tube 11. In the illustrated example, the outer peripheral surface 121o and the inner peripheral surface 11i are in contact with each other over the entire circumferential direction, but the outer peripheral surface 121o and the inner peripheral surface 11i may only be in contact with each other over a portion of the circumferential direction, and there may be portions where they do not contact each other.

[0063] The second distal tube 21 of the OTW tube 20 is disposed distally of the second proximal tube 22, and the distal end of the second proximal tube 22 is joined to the proximal end of the second distal tube 21. This forms the OTW tube 20 having the OTW lumen 20L. The distal end of the second proximal tube 22 is provided with a second tapered section 221, in which the outer diameter of the second proximal tube 22 narrows from the proximal end toward the distal end. In the second tapered section 221, the wall thickness of the second proximal tube 22 gradually decreases toward the distal end. The second tapered section 221 is covered by the proximal end of the second distal tube 21. In other words, the second distal tube 21 and the second proximal tube 22 are arranged to overlap within the range of the second tapered section 221.

[0064] The second distal tube 21 and the second proximal tube 22 are joined in an incompatible state at the overlapping portion of the second distal tube 21 and the second proximal tube 22. Hereinafter, this portion will be referred to as the "second joint portion." Similar to the first tapered portion 121 described in FIG. 7A, at the second joint portion, the outer circumferential surface of the second tapered portion 221 contacts the inner circumferential surface of the second distal tube 21.

[0065] As shown in FIG. 6 , in the longitudinal direction of the catheter 1, the distal end position P2 of the second proximal tube 22 is located more distally than the distal end position P1 of the first proximal tube 12. That is, the first joint and the second joint are offset in the longitudinal direction of the catheter 1. In other words, the first joint and the second joint are located at different positions in the longitudinal direction of the catheter 1. Furthermore, in the longitudinal direction of the catheter 1, the proximal end position of the second tapered section 221 is located more distally than the distal end position P1 of the first proximal tube 12. That is, the first joint and the second joint are located at different positions in the longitudinal direction of the catheter 1 and do not overlap each other. Furthermore, in the longitudinal direction of the catheter 1, the length L1 of the first tapered section 121 is longer than the length L2 of the second tapered section 221. The lengths L1 and L2 can be determined arbitrarily as long as they satisfy the above-described relationship.

[0066] 3(E), the outer diameter Φ12 of the first proximal tube 12 is larger than the outer diameter Φ22 of the second proximal tube 22. Here, the outer diameter Φ12 refers to the outer diameter of the first proximal tube 12 on the proximal side of the first tapered portion 121. Similarly, the outer diameter Φ22 refers to the outer diameter of the second proximal tube 22 on the proximal side of the second tapered portion 221.

[0067] 6, the base end of the RX tube 30 (third tube) is located between the tip and base ends of the first tapered portion 121. In other words, the base end of the RX tube 30 is located within the range in which the first tapered portion 121 is provided.

[0068] 6 , the heat shrink tube 90 bundles together a portion of the distal end side of the first proximal tube 12 of the sensor tube 10 and a portion of the distal end side of the second proximal tube 22 of the OTW tube 20. The heat shrink tube 90 is disposed between the distal end and the proximal end of the first tapered portion 121. In other words, the heat shrink tube 90 is disposed within the range in which the first tapered portion 121 is provided.

[0069] As shown in FIG. 7B , the first tapered portion 121 of the first base-side tube 12 and the second base-side tube 22 are covered with a heat-shrinkable tube 90, with portions of their outer circumferential surfaces 121o, 22o in contact with each other. A gap SP is formed in the area surrounded by the outer circumferential surfaces 121o, 22o and the inner circumferential surface 90i of the heat-shrinkable tube 90. The gap SP exists on both sides of the contact portion between the tubes 12, 22. The heat-shrinkable tube 90 has a protrusion 91 that protrudes from one of the gaps SP (specifically, the gap SP closer to the RX tube 30). On the opposite side (outer circumferential surface side) of the heat-shrinkable tube 90 from the protrusion 91, a recess 92 is formed, where the heat-shrinkable tube 90 is recessed toward the contact portion between the tubes 12, 22. The RX tube 30 (third tube) is disposed in contact with the recess 92 in the outer circumferential surface of the heat-shrinkable tube 90. With this configuration, the outer diameter of the catheter 1 in the cross section taken along the line GG shown in FIG. 7(B) can be reduced.

[0070] In the overlapping portion of the heat-shrinkable tube 90 and the first outer tube 50, the first outer tube 50 covers the heat-shrinkable tube 90 and the RX tube 30 that is disposed in contact with the outer peripheral surface of the heat-shrinkable tube 90 (FIG. 7B). The outer peripheral surfaces of the heat-shrinkable tube 90 and the RX tube 30 are integrally fixed by the melt-molded first outer tube 50.

[0071] Here, sections S1 to S4 along the longitudinal direction of the catheter 1 are defined. As shown in Fig. 6, section S1 is a section from the distal end of the second distal tube 21 to the distal end P2 of the second proximal tube 22. Section S2 is a section from the distal end P2 of the second proximal tube 22 to the distal end P1 of the first proximal tube 12. Section S3 is a section from the distal end to the proximal end of the first tapered section 121, in other words, a section in which the first tapered section 121 is provided. Section S4 is a section from the proximal end of the first tapered section 121 to the proximal end of the first proximal tube 12.

[0072] Section S1 is a section containing the first distal tube 11 and the second distal tube 21, which have relatively low second and fourth bending stiffnesses, and therefore has a relatively low stiffness of the catheter 1. Section S4 is a section containing the first proximal tube 12 and the second proximal tube 22, which have relatively high first and third bending stiffnesses, and which does not contain a tapered portion in either the first proximal tube 12 or the second proximal tube 22, and therefore has a relatively high stiffness of the catheter 1. Section S2 is a section containing the first distal tube 11, which has a relatively low second bending stiffness, and the second proximal tube 22, which has a relatively high third bending stiffness, and therefore has a higher stiffness of the catheter 1 than Section S1 and lower than Section S4. Although section S3 includes the first proximal tube 12 and the second proximal tube 22, which have relatively high first and third bending stiffnesses, the first proximal tube 12 is formed with the first tapered portion 121, and therefore the stiffness of the catheter 1 is higher than sections S1 and S2 and lower than section S4. That is, in sections S1 to S4 along the longitudinal direction of the catheter 1, the stiffness of the catheter 1 satisfies the relationship S1<S2<S3<S4. In this way, the catheter 1 of this embodiment can achieve a gradual change in stiffness from the distal end to the proximal end of the catheter 1.

[0073] 8 and 9 are diagrams illustrating a method for manufacturing the catheter 1. In Fig. 8 and Fig. 9, a case where the sensor tube 10 is formed by joining a first distal tube 11 and a first proximal tube 12 is illustrated. However, the same method as in Fig. 8 and Fig. 9 can also be used when the OTW tube 20 is formed by joining a second distal tube 21 and a second proximal tube 22. Furthermore, in Fig. 8, the tubes that are the material for the first proximal tube 12 are designated by reference numerals suffixed with "a."

[0074] 8A shows the step of placing the tube 12a in the constriction forming process. As shown in FIG. 8A, an operator prepares the tube 12a, which is a long tubular body, and inserts a core C1 into the tube 12a. At this time, the distal end of the core C1 is positioned closer to the base end than the distal end of the tube 12a. In this embodiment, a PEEK tube is used as the tube 12a.

[0075] FIG. 8B illustrates the step of forming the constriction 129 during the constriction forming process. As shown in FIG. 8B , the operator holds the portion of the tube 12a distal from the core C1 with the first chuck HG1 and the distal end of the tube 12a with the second chuck HG2. In this state, the operator heats a portion of the tube 12a distal to the first chuck HG1 (circled in dashed lines) at a predetermined temperature while pulling the second chuck HG2 in the direction of the white arrow to stretch the tube 12a. The heating temperature is the temperature at which the tube 12a melts and deforms. In this embodiment, the heating temperature is 100° C. or more higher than the melting point of the first distal tube 11. The first chuck HG1 can be, for example, a vice, and the second chuck HG2 can be, for example, needle-nose pliers.

[0076] FIG. 8(C) illustrates the tapered portion forming process. As shown in FIG. 8(C), the above-described heating and drawing of the tube 12a forms a constriction 129, circled by a dashed line, at the distal end of the core C1 of the tube 12a. The constriction 129 is the portion of the tube 12a where the outer diameter is smallest. Then, as shown in FIG. 8(C), the worker cuts the tube 12a at the constriction 129 using a feather cutter C2. This allows the formation of a first proximal tube 12 having a first tapered portion 121 at its distal end (FIG. 9(A)).

[0077] 9A illustrates the state before insertion during the insertion process. As shown in FIG. 9A, the operator prepares the first distal tube 11. The outer diameter of the first distal tube 11 at its proximal end is defined as an outer diameter Φ11po, and the inner diameter of the first distal tube 11 at its proximal end is defined as an inner diameter Φ11pi. The outer diameter of the first distal tube 11 at a position PA (hereinafter also referred to as a "predetermined position PA") that is an arbitrary distance from the proximal end of the first distal tube 11 in the longitudinal direction (the longitudinal direction of the first distal tube 11) is defined as an outer diameter Φ11ao, and the inner diameter at the predetermined position PA is defined as an inner diameter Φ11ai. In this case, the outer diameter Φ11po of the first distal tube 11 at its proximal end is substantially the same as the outer diameter Φ11ao at the predetermined position PA. Furthermore, the inner diameter Φ11pi of the first distal tube 11 at its proximal end is substantially the same as the inner diameter Φ11ai at the predetermined position PA. 9A , the operator inserts the first tapered portion 121 of the first proximal tube 12 into the first distal tube 11. In the illustrated example, a distal portion of the first tapered portion 121 is inserted into the first distal tube 11.

[0078] 9(B) shows the state after insertion during the insertion process. As a result of the insertion shown in FIG. 9(A), the first distal tube 11 and the first proximal tube 12 are arranged with the outer circumferential surface 121o of the first tapered portion 121 of the first proximal tube 12 in contact with the inner circumferential surface 11i of the first distal tube 11, as shown in FIG.

[0079] 9(C) illustrates the joining process. As shown in FIG. 9(C), after inserting the first proximal tube 12 into the first distal tube 11, the worker applies an adhesive, such as an epoxy adhesive, to the outer circumferential surface of the step LP between the first distal tube 11 and the first proximal tube 12. The step LP is located closer to the proximal end of the first distal tube 11 and is a portion where the outer diameter of the first proximal tube 12 is reduced by the first tapered portion 121. Note that application of adhesive to the step LP may be omitted. Through the above procedure, the sensor tube 10 is prepared, in which the distal end of the first proximal tube 12 and the proximal end of the first distal tube 11 are joined by contacting each other in an incompatible state.

[0080] Thereafter, the worker prepares the OTW tube 20 using the same procedure as described above, and then bundles the sensor tube 10 and the OTW tube 20 together using the heat-shrink tube 90. The worker then places the RX tube 30 on the tubes 10, 20 bundled together using the heat-shrink tube 90, and integrates them using the first outer tube 50. The sensor tube 10 (first distal tube 11 and first proximal tube 12) and the OTW tube 20 (second distal tube 21 and second proximal tube 22) are fixed by the first outer tube 50. Note that the step portion LP in FIG. 9C is not visible on the outside because it is covered by the thick portion of the first outer tube 50 as shown in FIG. 7A.

[0081] As described above, according to the catheter 1 of the first embodiment, as shown in FIG. 6 , the distal end position P2 of the second proximal tube 22 is located distal to the distal end position P1 of the first proximal tube 12. That is, the first joint where the first distal tube 11 and the first proximal tube 12 are joined and the second joint where the second distal tube 21 and the second proximal tube 22 are joined are offset (located at different positions) in the longitudinal direction of the catheter 1 (medical device). Therefore, compared to when the first joint and the second joint are located at the same position, a gradual change in stiffness of the catheter 1 can be achieved ( FIG. 6 : S1 < S2 < S3 < S4), and kinking of the catheter 1 can be suppressed. As a result, buckling of the catheter 1 can be suppressed when a pushing force is applied to the catheter 1 during use.

[0082] Furthermore, according to the catheter 1 of the first embodiment, the first tapered portion 121 is provided at the distal end of the first proximal tube 12, and the first tapered portion 121 makes it easy to connect the first proximal tube 12 to the first distal tube 11. Similarly, the second tapered portion 221 is provided at the distal end of the second proximal tube 22, and the second tapered portion 221 makes it easy to connect the second proximal tube 22 to the second distal tube 21. Furthermore, by making the length L1 of the first tapered portion 121 different from the length L2 of the second tapered portion 221, the gradual change in stiffness can be made even better.

[0083] Furthermore, according to the catheter 1 of the first embodiment, since the catheter 1 is provided with the RX tube 30, the catheter 1 (medical device) can be configured to have an RX lumen 30L (third lumen).

[0084] Furthermore, according to the catheter 1 of the first embodiment, the proximal position of the second tapered section 221 is located distal to the distal position P1 of the first proximal tube 12 in the longitudinal direction of the catheter 1. In other words, the first tapered section 121 and the second tapered section 221 do not overlap in the longitudinal direction of the catheter 1 but are located at different positions. Therefore, as described with reference to FIG. 6 , it is possible to reduce the variation in the outer diameters of the first proximal tube 12 and the second proximal tube 22 in the longitudinal section of the catheter 1 where three tubes (specifically, the first proximal tube 12, the second proximal tube 22, and the RX tube 30 as the third tube) are present. As a result, as shown in FIG. 7B , it is possible to reduce the deviation in the position of the RX tube 30 (the RX tube 30 being positioned displaced relative to either the first proximal tube 12 or the second proximal tube 22). In other words, for example, if the first proximal tube does not have the first tapered portion 121, there is a risk that the RX tube 30 will be biased toward one of the first and second proximal tubes due to the difference in outer diameter between the relatively large-diameter first proximal tube and the relatively small-diameter second proximal tube. In this regard, in the catheter 1 (medical device) of this embodiment, the first proximal tube 12 has the first tapered portion 121, and therefore such bias can be suppressed, as shown in FIG. 7(B).

[0085] Furthermore, according to the catheter 1 of the first embodiment, as shown in Fig. 7(B), the first proximal tube 12 and the second proximal tube 22 can be bundled together without adhesive by using a heat-shrinkable tube 90. Also, as shown in Fig. 6, the heat-shrinkable tube 90 is disposed between the distal end and the proximal end of the first tapered section 121, and therefore the presence of the heat-shrinkable tube 90 can prevent the outer diameter of the catheter 1 (medical device) from increasing.

[0086] Furthermore, according to the catheter 1 of the first embodiment, it is possible to join tubes with different melting points because the melting point of the first proximal tube 12 is higher than the melting point of the first distal tube 11. Furthermore, according to the catheter 1 of the first embodiment, the first proximal tube 12 and the first distal tube 11 are in contact with each other in an immiscible state, so it is possible to join the tubes without causing them to become miscible with each other.

[0087] 8A to 8C and 9A, the manufacturing method of the catheter 1 of the first embodiment allows the first base-end tube 12 and the first distal-end tube 11 to be joined together by utilizing the first tapered portion 121 (tapered portion) formed at the distal end of the first base-end tube 12. Furthermore, as explained in FIG. 8B, the manufacturing method of the catheter 1 of the first embodiment allows the first base-end tube 12 and the first distal-end tube 11 to be joined together even if the melting points of the first base-end tube 12 and the first distal-end tube 11 differ by 100°C or more. Furthermore, as explained in FIG. 9A and 9B, the manufacturing method of the catheter 1 of the first embodiment allows the first base-end tube 12 and the first distal-end tube 11 to be joined together by utilizing the first tapered portion 121 without processing the first base-end tube 12 (for example, flaring).

[0088] Second Embodiment Fig. 10 is a diagram illustrating a method for manufacturing a catheter 1A according to a second embodiment. The catheter 1A according to the second embodiment differs from the first embodiment described in Fig. 9 in the contents of the insertion step and the joining step. In the second embodiment, the constriction forming step and the tapered portion forming step are the same as those in the first embodiment.

[0089] FIG. 10A illustrates a state before insertion during the insertion process. As shown in FIG. 10A, the operator prepares a first distal tube 11A. Unlike the first distal tube 11 of the first embodiment, the first distal tube 11A has a flared proximal end. Specifically, the outer diameter Φ11poA at the proximal end of the first distal tube 11A is larger than the outer diameter Φ11aoA at the predetermined position PA. Furthermore, the inner diameter Φ11piA at the proximal end of the first distal tube 11A is larger than the inner diameter Φ11aiA at the predetermined position PA. In other words, the outer and inner diameters of the first distal tube 11A gradually increase in a portion toward the proximal end. The portion of the first distal tube 11A where the outer diameter Φ11poA and inner diameter Φ11piA are enlarged is also referred to as the "flared portion 111." As shown by the white arrow in FIG. 10A, the operator inserts the first tapered portion 121 of the first base-end tube 12 into the flared portion 111 of the first distal-end tube 11A.

[0090] 10(B) shows the state after insertion during the insertion process. As a result of the process shown in FIG. 10(A), the first distal tube 11A and the first proximal tube 12 are arranged with the outer peripheral surface 121o of the first tapered portion 121 of the first proximal tube 12 in contact with the inner peripheral surface 111i of the flared portion 111 of the first distal tube 11A, as shown in FIG. 10(B). As shown in the figure, in this embodiment, the proximal end of the first distal tube 11A is formed as the flared portion 111, so when the first proximal tube 12 is inserted into the first distal tube 11A, the step LP described in the first embodiment is not formed (or the step LP is reduced).

[0091] 10C shows the joining step. As shown in FIG. 10C, after inserting the first proximal tube 12 into the first distal tube 11A, the worker applies an adhesive, such as an epoxy adhesive, to the outer circumferential surface of the first proximal tube 12 located proximally of the first distal tube 11A. The subsequent steps are the same as those described in the first embodiment.

[0092] As described above, the method for manufacturing the catheter 1A can be modified in various ways, and the occurrence of the step LP can be suppressed by forming a flared portion 111 at the base end of the first distal tube 11A. The modifications described above are merely examples, and the method for manufacturing the catheter 1A can be modified in various ways. For example, the adhesive may be applied to the outer peripheral surface of the first tapered portion 121 of the first proximal tube 12 in the joining step. The catheter 1A of the second embodiment and the method for manufacturing the catheter 1A described above can also achieve the same effects as those of the first embodiment described above.

[0093] 11 is an enlarged view of the vicinity of the tube joint of a catheter 1B of a third embodiment. The catheter 1B of the third embodiment has the same configuration as that described in the first embodiment, but includes a sensor tube 10B instead of the sensor tube 10. The sensor tube 10B includes a first base-end tube 12B having a first tapered portion 121B instead of the first base-end tube 12 described in the first embodiment.

[0094] The first tapered portion 121B has a length L1B in the longitudinal direction of the catheter 1B that is shorter than the length L1 described in the first embodiment. In the example shown, the length L1B of the first tapered portion 121B is the same as the length L2 of the second tapered portion 221. As a result, in the catheter 1B, the base end of the RX tube 30 is located closer to the base end than the first tapered portion 121B.

[0095] As described above, the configuration of the catheter 1B can be modified in various ways, and the length L1B of the first tapered portion 121B and the length L2 of the second tapered portion 221 can be changed as desired. For example, the length L1B of the first tapered portion 121B may be shorter than the length L2 of the second tapered portion 221. Either the length L1B or the length L2 may be set to zero. In this case, either the first base-end tube 12B or the second base-end tube 22 does not have a tapered portion. The catheter 1B of the third embodiment described above can also achieve the same effects as the first embodiment described above.

[0096] <Fourth embodiment> Figure 12 is a diagram illustrating a method for manufacturing a catheter 1C according to a fourth embodiment. The catheter 1C according to the fourth embodiment differs from the first embodiment described in Figure 9 in the content of the insertion step. In the fourth embodiment, the constriction forming step, the tapered portion forming step, and the joining step are the same as those in the first embodiment.

[0097] FIG. 12A illustrates the state before insertion during the insertion process. As shown in FIG. 12A , the operator prepares the first distal tube 11 and the connecting member 15. The connecting member 15 is a member disposed between the first distal tube 11 and the first proximal tube 12 to connect them. In the illustrated example, the connecting member 15 is a tapered tubular body whose outer diameter and inner diameter each decrease from the proximal end to the distal end. The connecting member 15 may be, for example, a PTFE tube. As indicated by the white arrows in FIG. 12A , the operator inserts the connecting member 15 into the first distal tube 11 and the first proximal tube 12 into the connecting member 15.

[0098] Figure 12(B) shows the state after insertion during the insertion process. As a result of Figure 12(A), as shown in Figure 12(B), the first base-end tube 12 and the first distal-end tube 11 are joined together in an incompatible state without contacting each other via the connecting member 15. Specifically, the outer peripheral surface 121o of the first tapered portion 121 of the first base-end tube 12 is in contact with the inner peripheral surface of the connecting member 15. Furthermore, the inner peripheral surface 11i of the first distal-end tube 11A is in contact with the outer peripheral surface of the connecting member 15. The subsequent procedures are the same as those described in the first embodiment.

[0099] As described above, the method for manufacturing the catheter 1C can be modified in various ways, and the first proximal tube 12 and the first distal tube 11 can be joined in an incompatible state without contacting each other by using the connecting member 15. The above-described modifications are merely examples, and the method for manufacturing the catheter 1C can be modified in various ways. For example, the adhesive may be applied to at least one of the outer circumferential surface of the connecting member 15 and the outer circumferential surface of the first tapered portion 121 in the joining step. The catheter 1C of the fourth embodiment and the method for manufacturing the catheter 1C described above can also achieve the same effects as those of the first embodiment described above.

[0100] 13 is an enlarged view of the vicinity of the tube joint of a catheter 1D of a fifth embodiment. The catheter 1D of the fifth embodiment does not include the second outer tube 80 and the heat-shrinkable tube 90 in the configuration described in the first embodiment. In the fifth embodiment, the first proximal tube 12 and the second proximal tube 22 are joined to each other on the proximal side of the first outer tube 50 by thermal welding or any bonding agent (for example, a metal solder such as silver solder, gold solder, zinc, Sn—Ag alloy, or Au—Sn alloy, or an adhesive such as an epoxy adhesive).

[0101] As described above, the configuration of the catheter 1D can be modified in various ways, and it is also possible to omit at least one of the second outer tube 80 and the heat-shrinkable tube 90. The catheter 1D of the fifth embodiment as described above can also achieve the same effects as those of the first embodiment.

[0102] <Modifications of this embodiment> The present invention is not limited to the above-described embodiment, and can be implemented in various forms without departing from the spirit of the present invention. For example, the following modifications are also possible.

[0103] [Modification 1] In the above first to fifth embodiments, one example of the configuration of the catheters 1, 1A to 1D is shown. However, the configuration of the catheters 1, 1A to 1D can be modified in various ways.

[0104] For example, the distal end positions P1 and P2 in the longitudinal direction of the catheter 1 may be reversed. That is, the distal end position P2 of the second proximal tube 22 may be located closer to the proximal end than the distal end position P1 of the first proximal tube 12. For example, the RX tube 30 may be omitted, resulting in a catheter 1 having two lumens. For example, the outer diameters of the first proximal tube 12 and the second proximal tube 22 may be equal, or the relationship in magnitude between the outer diameters may be reversed from that in the first embodiment. For example, the melting point of the first proximal tube 12 may be equal to that of the first distal tube 11, or the relationship in magnitude between the melting points may be reversed from that in the first embodiment. For example, the first proximal tube 12 and the first distal tube 11 may be joined in a compatible state. The same applies to the second distal tube 21 and the second proximal tube 22 in terms of outer diameter, melting point, and compatibility.

[0105] For example, the outer circumferential surfaces of the first outer tube 50, the heat-shrinkable tube 90, and the second outer tube 80, or the outer circumferential surface of the catheter 1 including these, may be coated with a hydrophilic resin or a hydrophobic resin. For example, the sensor 70 is built into the sensor lumen 10L of the sensor tube 10 and is configured to be unremovable from the catheter 1. However, the sensor 70 may also be configured to be removable from the catheter 1. In other words, the catheter 1 does not have to include the sensor 70 as a component.

[0106] For example, at least one of the distal tip 40, the first marker 41, and the second marker 42 may be omitted. For example, the shapes of the distal tip 40, the first marker 41, and the second marker 42 can be changed as desired. The distal tip 40 may have a constant outer diameter from the distal end to the proximal end, and the cross-sectional shape may be asymmetrical. The first marker 41 and the second marker 42 may have a shape other than a ring shape (for example, a ring shape cut at an arbitrary angle, a wire shape, or a coil shape formed by spirally winding a wire).

[0107] For example, the positions of the distal tip 40, the first marker 41, and the second marker 42 can be changed as desired. The first marker 41 may not overlap the distal tip 40, but may be positioned adjacent to the proximal end of the distal tip 40 or at a position distant from the proximal end of the distal tip 40. The second marker 42 may be positioned at a position other than adjacent to the distal end of the distal opening 201 of the OTW tube 20 (for example, at a position distant from the distal opening 201). The first marker 41 and the second marker 42 may be positioned on a tube (sensor tube 10 or OTW tube 20) different from the RX tube 30. The first marker 41 and the second marker 42 may be positioned on the same tube as described above, or may be positioned on different tubes.

[0108] For example, at least one of the first outer tube 50 and the second outer tube 80 may be omitted. For example, in the above embodiment, the first outer tube 50 and the second outer tube 80 each consist of a single layer, but at least one of the first outer tube 50 and the second outer tube 80 may consist of two or more layers. For example, in the above embodiment, the cross-sectional shape of the portion of the catheter 1 covered by the first outer tube 50 is a rounded triangle, but it may be any shape, such as a circle or an ellipse. For example, in the above embodiment, the cross-sectional shape of the portion of the catheter 1 covered by the second outer tube 80 is an ellipse, but it may be any shape, such as a circle or a rounded triangle. For example, at least one of the first outer tube 50 and the second outer tube 80 may have an outer shape that follows the contour of the outer peripheral surface of the tube 10, 20 (or tubes 10, 20, 30).

[0109] For example, the shapes of the branch connector 60, the first reinforcing member 61 to the third reinforcing member 63, the tubular member 64, the connector 65, and the connector 25 described above are merely examples and may be changed as desired. For example, at least a portion of the branch connector 60, the first reinforcing member 61, the second reinforcing member 62, and the tubular member 64 may be configured as a single member or may be omitted. For example, the third reinforcing member 63 and the connector 25 may be configured as a single member. For example, the tubular member 64 may be provided with a mechanism (e.g., scales or stoppers provided at predetermined intervals in the longitudinal direction, or scales or stoppers provided at predetermined intervals in the circumferential direction) that assists in adjusting at least one of the front-to-rear position of the sensor 70 and the orientation of the sensor 70 in the circumferential direction.

[0110] For example, the manufacturing methods of catheters 1, 1A-1D described in Figures 8, 9, 10, and 12 are merely examples, and various modifications are possible. For example, the heating temperature in the constriction forming step can be changed as desired as long as it is a temperature at which tube 12a melts and deforms, and does not have to be a temperature 100°C or more higher than the melting point of first distal tube 11. For example, additional steps may be included between the above-described steps, such as pre-treatment for processing or for arranging other components not described.

[0111] [Variation 2] The configurations of the catheters 1, 1A-1D of the first to fifth embodiments and the configuration of the catheters 1, 1A-1D of Variation 1 may be combined as appropriate. For example, the catheter 1A, 1C configured by the method described in either the second or fourth embodiment may be combined with the omission of the second outer tube 80 or the heat-shrinkable tube 90 described in the fifth embodiment. For example, the catheter 1B described in the third embodiment may be combined with the omission of the second outer tube 80 or the heat-shrinkable tube 90 described in the fifth embodiment.

[0112] This aspect has been described above based on embodiments and modifications. However, the above-described embodiments are intended to facilitate understanding of this aspect and are not intended to limit this aspect. This aspect may be modified or improved without departing from the spirit and scope of the claims, and equivalents thereof are included in this aspect. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate.

Claims

1. It is a medical device, A first base end tube having a first bending rigidity and constituting a part of the first lumen, Having a second bending rigidity lower than the first bending rigidity, positioned on the tip side of the first base end tube, with the tip of the first base end tube and its own base end joined, the first tip end tube constitutes a part of the first lumen, A second base end tube having a third bending rigidity and constituting a part of the second lumen, A second tip tube having a fourth bending rigidity lower than the third bending rigidity, positioned on the tip side of the second base tube, with its own base end joined to the tip of the second base tube, and constituting a part of the second lumen, wherein the tip position of the second base tube is located on the tip side of the first base tube in the longitudinal direction of the medical device, A medical device equipped with the following features.

2. A medical device according to claim 1, A medical device in which the tip of the first proximal tube is provided with a tapered portion whose outer diameter decreases from the proximal end to the tip, and the outer surface of the tapered portion is in contact with the inner surface of the first tip tube.

3. A medical device according to claim 2, further, A medical device comprising a third lumen and a third tube whose base is located between the tip and base of the tapered portion.

4. A medical device according to claim 2, The first base end tube and the second base end tube are bundled together with heat shrink tubing. The heat-shrinkable tube is positioned between the tip and base of the tapered portion of the medical device.

5. A medical device according to claim 2, The tapered portion is a first tapered portion, The tip of the second base end tube is provided with a second tapered portion in which the outer diameter decreases from the base end to the tip, and the outer surface of the second tapered portion is in contact with the inner surface of the second tip end tube. A medical device wherein the length of the first tapered portion in the longitudinal direction of the medical device is longer than the length of the second tapered portion.

6. A medical device according to claim 5, The outer diameter of the first proximal end tube is larger than the outer diameter of the second proximal end tube. A medical device wherein, in the longitudinal direction of the medical device, the base end position of the second tapered portion is located closer to the tip than the tip position of the first base end tube.

7. A medical device according to any one of claims 1 to 6, A medical device in which the melting point of the first proximal end tube is higher than the melting point of the first tip end tube.

8. A medical device according to any one of claims 1 to 6, A medical device in which the first proximal tube and the first distal tube are in contact in an incompatible state.

9. A medical device according to any one of claims 1 to 6, A medical device in which the outer diameter of the first proximal end tube is larger than the outer diameter of the second proximal end tube.

10. A method for manufacturing a medical device, By stretching the first proximal end tube, a constriction is formed in the first proximal end tube. By cutting the first base end tube at the constriction, a tapered portion is formed at the tip of the first base end tube. Insert at least a portion of the tapered portion of the first proximal end tube into the first tip end tube. A method for manufacturing medical devices, including the following.

11. A method for manufacturing a medical device according to claim 10, A method for manufacturing a medical device, comprising heating the first proximal end tube to a temperature at least 100°C higher than the melting point of the first tip end tube when stretching the first proximal end tube.

12. A method for manufacturing a medical device according to claim 10 or claim 11, Before insertion, the outer diameter at the base end of the first tip tube is substantially the same as the outer diameter at a predetermined position away from the base end of the first tip tube in the longitudinal direction. A method for manufacturing a medical device, wherein, before insertion, the inner diameter at the base end of the first tip tube is substantially the same as the inner diameter at the predetermined position.