Catheter and fixing method of marker member to catheter

Abstract

To provide a catheter capable of reducing the outer diameter of a tubular body while fixing a marker member so that it does not fall off, and to provide a method for fixing the marker member to the catheter.SOLUTION: A catheter 10 includes a long-sized tubular body 20. In the catheter 10, the tubular body 20 includes: a long-sized tubular main body 23 having a lumen; a marker member 25 disposed at a distal end portion of the tubular main body 23 and including an inner surface 25a facing a center of the tubular main body 23 and an outer surface 25b facing an opposite side of the inner surface 25a; and a covering portion 81 welded to the distal end portion of the tubular main body 23 so as to cover only a part in a circumferential direction of the tubular main body 23 together with the outer surface 25b of the marker member 25. A welding interface 26 between the tubular main body 23 and the covering portion 81 is disposed so as to surround a peripheral edge of the marker member 25.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a catheter to be inserted into a cavity of a living body such as the heart or a blood vessel, and a method for fixing a marker member to the catheter. [Background technology]

[0002] Catheters with long tubular bodies are used for the treatment and examination of various diseases. Catheters are inserted into the internal cavities of living bodies, such as the heart and blood vessels. To confirm the position of the catheter inserted into the living body, a marker member is provided at the tip of the tubular body, and the marker member is visually recognized under X-ray imaging.

[0003] The marker member must be secured so as not to fall off from the tubular body. If the marker member is simply bonded to the tubular body with an adhesive, there is a possibility that the marker member may fall off during use. For this reason, a catheter is known in which an outer-layer tube is placed over a cylindrical marker member disposed on the outer surface of an inner-layer tube, and the inner-layer tube and the outer-layer tube are heat-welded (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6308343 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to fix the marker member to the tubular body, if the marker member is placed on the outer surface of the molded tubular body and then a tubular member is placed outside the marker member, the outer diameter of the tubular body will increase. If the outer diameter of the tubular body is large, the tubular body will be easily caught on the inner surface of the sheath used to insert the catheter into the lumen of the living body, making it difficult to insert the tubular body or creating a risk of damaging the tubular body.

[0006] The present invention has been made to solve the above-mentioned problems, and aims to provide a catheter and a method for fixing a marker member to a catheter that can reduce the outer diameter of the tubular body while fixing the marker member so that it does not fall off. [Means for solving the problem]

[0007] (1) A catheter that achieves the above-mentioned object is a catheter having a long tubular body, the tubular body having a long tubular body including an inner lumen, a marker member disposed at the tip of the tubular body and including an inner surface facing the center of the tubular body and an outer surface facing away from the inner surface, and a covering portion welded to the tip of the tubular body so as to cover only a portion of the circumference of the tubular body together with the outer surface of the marker member, and the weld interface between the tubular body and the covering portion is disposed so as to surround the periphery of the marker member.

[0008] (7) A method for fixing a marker member to a catheter that achieves the above-mentioned object is a method for fixing a marker member to a catheter having a long tubular body including an inner lumen, in which the marker member is placed on the outer surface of the tip of the tubular body, a covering portion is placed on only a portion of the circumferential direction of the tubular body so as to cover the marker member, and the covering portion is welded to the outer surface of the tubular body to form a weld interface that surrounds the periphery of the marker member. [Effects of the Invention]

[0009] In the catheter (1) configured as described above, the covering portion covers only a portion of the circumferential direction of the tubular body, so that the outer diameter of the tubular body can be reduced while the marker member is covered by the covering portion. By reducing the outer diameter of the tubular body, the catheter can be prevented from getting caught on the inner surface of the sheath used to insert the catheter into a lumen of a living body, allowing the tubular body to be inserted smoothly.

[0010] (2) In the catheter of (1) above, the distal end of the tubular body may have a circular cross section taken along a plane perpendicular to the longitudinal axis, and the outer surface of the tubular body may have a raised portion formed by the covering portion and raised from the circular shape along a circumferential portion of the tubular body, and the welded interface may be formed as a closed line along the periphery of the raised portion. This allows the catheter to reduce the outer diameter of the tubular body, since the raised portion is formed only along a circumferential portion of the tubular body. Furthermore, the welded interface surrounds the entire circumference of the marker member, reliably preventing the marker member from falling off the tubular body.

[0011] (3) In the catheter of (2) above, the outer surface of the tubular body may have a constricted portion that surrounds at least the base end side of the protruding portion and both sides in the circumferential direction of the tubular body of the circumferential edge of the protruding portion and extends to the opposite side of the protruding portion and the center of the tubular body, and the constricted portion may be recessed toward the center of the tubular body more than the outer surface of the tubular body near the base end of the constricted portion. This allows the outer diameter of the catheter to be made smaller, making it easier to insert the catheter into a sheath.

[0012] (4) In the catheter of any one of (1) to (3) above, the tubular body may have a distal opening communicating with the lumen, the tubular body may have a distal cap sealing the distal opening of the tubular body, the distal cap may have an outer peripheral welding surface to be welded to the inner surface of the tubular body, and the distal end of the marker member may be located proximal to the proximal end of the outer peripheral welding surface. This allows the marker member to avoid interference when attaching the distal cap to the distal end of the tubular body.

[0013] (5) In any of the catheters (1) to (4) above, the tubular body may have a small-diameter portion at the distal end that is smaller in outer diameter than other portions, and the marker member and the welded interface may be disposed at the small-diameter portion. This makes it possible to further suppress an increase in the outer diameter of the tubular body due to the marker member and the covering portion.

[0014] (6) In any of the catheters (1) to (4) above, the tubular main body may have a small-diameter portion at the distal end that is smaller in outer diameter than other portions, the marker member may be disposed at the small-diameter portion, and at least a portion of the welded interface may be located outside the small-diameter portion. This allows the catheter to suppress an increase in the outer diameter of the tubular body due to the marker member and the covering portion, while also suppressing kinking at the distal end of the tubular body.

[0015] In the method (7) for fixing a marker member to a catheter configured as described above, the covering portion covers only a portion of the circumferential direction of the tubular body, so that the marker member can be covered by the covering portion while the outer diameter of the tubular body can be reduced. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a front view of a catheter according to an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged cross-sectional view of the catheter near its tip taken along a plane along its longitudinal axis. [Figure 3] 1 is a cross-sectional view of a tube at a position where a marker member is arranged, taken along a plane perpendicular to the longitudinal axis direction. FIG. [Figure 4] FIG. 10 is a top view of the tubular body in the vicinity of the marker member. [Figure 5] FIG. 1 is an explanatory diagram showing the catheter of this embodiment and a treatment catheter inserted into the heart. [Figure 6] FIG. 10 is a perspective view of a tubular member divided into three parts. [Figure 7] 1 is a cross-sectional view of a tube in which a marker member and a covering portion are arranged on the tube, the cross-sectional view being taken along a plane perpendicular to the longitudinal axis direction. [Figure 8] 1 is an enlarged cross-sectional view of a tube in which a marker member, a covering portion, and a heat-shrinkable tube are arranged on the tube, the cross-sectional view being taken along a plane along the longitudinal direction. [Figure 9] 9 is an enlarged cross-sectional view of the tube cut along a plane along the longitudinal direction in a state in which a core bar is inserted into the tube and the heat-shrinkable tube is heated, following the state shown in FIG. 8. [Figure 10]10 is an enlarged cross-sectional view of the tube cut along a plane along the longitudinal direction in a state in which a marker member is fixed to the tube and then a tip cap is fixed to the tube. FIG. [Figure 11] 10 is an enlarged cross-sectional view of a modified example of the joining structure between the tubular body and the marker member, taken along a plane along the longitudinal axis of the tubular body. FIG. [Figure 12] 11 is an enlarged cross-sectional view of the tube of FIG. 10, in which a marker member, a covering portion, and a heat-shrinkable tube are arranged, taken along a plane along the longitudinal direction. [Figure 13] 1 is an enlarged cross-sectional view of a pipe body with a marker member embedded therein, cut along a plane along the longitudinal direction. [Figure 14] 1 is an enlarged cross-sectional view of a pipe having a marker member embedded therein, cut along a plane perpendicular to the longitudinal axis direction. [Figure 15] 10 is an enlarged cross-sectional view of a tube with a marker member embedded therein, taken along a plane along the longitudinal direction, in which a part of the covering portion is positioned distally of the small diameter portion. FIG. [Figure 16] FIG. 10 is an enlarged cross-sectional view of a tube cut along a plane perpendicular to the longitudinal axis direction, with a marker member and a covering portion disposed on the tube, when a small diameter portion is provided at a circumferential portion of the tube. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the dimensional proportions in the drawings may be exaggerated for the sake of explanation and may differ from the actual proportions. In this specification, the side that is inserted into the living body will be referred to as the "distal side" and the side that is operated will be referred to as the "proximal side."

[0018] The catheter 10 according to this embodiment is an ultrasound catheter that is inserted into the heart or a blood vessel to obtain ultrasound images transvascularly. As shown in Fig. 1, a housing 60 is provided at the proximal end of a long sheath 15. The sheath 15 includes a tubular body 20 and an inner tube 30, and a transducer unit 40 and a shaft 50 that holds the transducer unit 40 are provided inside the sheath 15.

[0019] The tubular body 20 can be inserted into a cavity in a living body. The tubular body 20 has a storage lumen 21 formed therein that communicates from the base end to the tip. The tubular body 20 also has a bent portion 24, and the portion distal to the bent portion 24 is bent at a bending angle θ with respect to a reference line X, which is the center line proximal to the bent portion 24. The bending angle θ of the bent portion 24 is not particularly limited, but is preferably 10° to 40°. The proximal end of the tubular body 20 is fixed to a housing 60. A tip cap 22 is attached to the tip of the tubular body 20.

[0020] The length from the bent portion 24 to the tip of the tubular body 20 is not particularly limited, but is preferably 20 to 150 mm. Therefore, the length along the reference line X of the offset portion (the portion where the axis is shifted from the reference line X in the direction perpendicular to the reference line X) distal to the bent portion 24 of the tubular body 20 can be appropriately set for use in the heart or blood vessels having a wide lumen. The offset amount is not particularly limited, but is preferably 5 to 30 mm. Having an appropriate offset amount makes it easy to bring the tubular body 20 close to the site to be observed in the heart or blood vessels having a wide lumen.

[0021] The tubular body 20 accommodates the transducer unit 40, inner tube 30, and shaft 50 in the accommodation lumen 21, which is an inner cavity. The transducer unit 40, inner tube 30, and shaft 50 in the tubular body 20 are movable within the accommodation lumen 21 along the axis of the tubular body 20. Furthermore, the transducer unit 40 and shaft 50 in the tubular body 20 are rotatable within the tubular body 20. The tubular body 20 is a cylindrical body that is open only at its base end and whose tip end is closed by a tip cap 22. The base end of the tubular body 20 is fixed to a housing 60. The base end of the tubular body 20 may be provided with a reinforcing member such as a braided wire.

[0022] In this embodiment, one bent portion 24 is provided, but it may be omitted, or two or more bent portions may be provided.

[0023] As shown in FIG. 2, a transducer unit 40 is disposed at the distal end of the sheath 15 , and the distal end opening of a tubular body 20 constituting the sheath 15 is sealed with a distal end cap 22 .

[0024] The transducer unit 40 transmits and receives ultrasound waves toward biological tissue inside the body. The transducer unit 40 includes an ultrasonic transducer 41 that transmits and receives ultrasound waves, and a transducer holder 42 on which the ultrasonic transducer 41 is disposed and which is fixed to the shaft 50. The transducer unit 40 is movable within the accommodation lumen 21 of the tubular body 20 in the axial direction of the tubular body 20, passing over the bending portion 24. The transducer unit 40 is also rotatable within the accommodation lumen 21 around the axial center.

[0025] The tip cap 22 has an insertion section 70 that extends from the tip opening of the tubular body 20 into the tubular body 20, and a tip protruding section 74 that protrudes from the tip opening of the tubular body 20 toward the tip side and has an outer diameter substantially the same as the outer diameter of the tubular body 20. The insertion section 70 has a base end section 71 that faces the ultrasonic vibrator 41, and an outer peripheral surface 72 that faces the inner peripheral surface of the tubular body 20. The outer peripheral surface 72 of the insertion section 70 has an outer peripheral welding surface 73 that is welded to the inner peripheral surface of the tubular body 20.

[0026] The distal protrusion 74 has a dome shape that is convex toward the distal end. The distal protrusion 74 forms the distal end of the catheter 10, and its dome shape prevents damage to living tissue.

[0027] The tubular body 20 has a long tubular body 23 including an inner cavity, a storage lumen 21, a marker member 25 arranged at the tip of the tubular body 23, and a covering portion 81 welded to the tip of the tubular body 23 so as to cover the marker member 25.

[0028] The marker member 25 is a small piece made of platinum or the like, and can be visualized under X-ray imaging. The marker member 25 includes an inner surface 25a facing the center of the tubular body 23 and an outer surface 25b facing away from the inner surface 25a. The marker member 25 is embedded in the tubular body 20 by being covered with a covering portion 81 that is welded to and integrated with the tubular body 23. The covering portion 81, together with the outer surface 25b of the marker member 25, covers only a portion of the circumferential direction of the tubular body 23. A weld interface 26 is formed on the outer surface of the tubular body 20 around the covering portion 81 welded to the tubular body 23. A constricted portion 28 is formed on the outer surface of the tubular body 20 around the weld interface 26. In this embodiment, the marker member 25 extends linearly along the axis, covering only a portion of the circumferential direction of the tubular body 23. This causes an ultrasound artifact to appear on the ultrasound image at the position of the marker member 25, and this artifact can be used to identify the orientation of the marker member 25 on the ultrasound image. Note that by setting the dimensions of the marker member 25 to cover ¼ or less, preferably ⅛ or less, of the circumferential direction of the tubular body 23, the orientation of the marker member 25 on the ultrasound image can be identified more reliably.

[0029] The tip of the marker member 25 is located on the proximal side of the proximal end of the outer peripheral welding surface 73 of the tip cap 22. Therefore, the area where the marker member 25 exists does not overlap with the area where the tip cap 22 is in contact with the tube 20 in the longitudinal direction of the tube 20. Furthermore, the welding interface 26 formed around the marker member 25 is located on the proximal side of the proximal end of the outer peripheral welding surface 73 of the tip cap 22. Therefore, the area where the welding interface 26 exists does not overlap with the area where the tip cap 22 is in contact with the tube 20 in the longitudinal direction of the tube 20.

[0030] As shown in FIG. 3 , the tubular body 23 has a circular cross section taken along a plane perpendicular to the longitudinal direction. The outer surface of the tubular body 20 has a raised portion 27 formed by a covering portion 81 at a circumferential portion of the tubular body 20, the raised portion 27 being raised radially from the circular shape of the tubular body 23. The marker member 25 is embedded inside the raised portion 27. The raised portion 27 has a welding interface 26 on both circumferential sides of the tubular body 23. The outer surface of the tubular body 20 also has constricted portions 28 on both circumferential sides of the raised portion 27 that are recessed toward the center of the tubular body 23. The constricted portions 28 are recessed toward the center of the tubular body 23 more than the outer surface of the tubular body 23 near the base end of the constricted portions 28.

[0031] As shown in FIG. 4 , a welded interface 26 formed by welding the tubular body 23 and the covering portion 81 on the outer surface of the tubular body 20 surrounds the periphery of the marker member 25, and a constricted portion 28 is formed around the welded interface 26. The welded interface 26 is formed, for example, in a ring shape so as to form a closed line along the periphery of the raised portion 27, and exists only partially around the tubular body 23 in the circumferential direction, not the entire circumference. In other words, the raised portion 27 surrounded by the welded interface 26 is formed only partially around the circumferential direction of the tubular body 20. Therefore, the catheter 10 can reduce the outer diameter of the tubular body 20 while covering the marker member 25 with the covering portion 81. In this specification, the outer diameter of the tubular body 20 refers to the average value of the distance from the center to the outer surface of the tubular body 20 over the entire circumference. Reducing the outer diameter of the tubular body 20 can prevent the tubular body 20 from getting caught on the inner surface of a sheath used to insert the catheter into a lumen of a living body, allowing the tubular body 20 to be inserted smoothly.

[0032] The constricted portion 28 surrounds the entire circumference of the raised portion 27 and extends to the opposite side of the raised portion 27 and the center of the tubular body 23. Note that when the marker member 25 is located near the tip of the tubular body 20, the constricted portion 28 does not need to surround the tip side of the raised portion 27.

[0033] 1, the inner tube 30 is a cylindrical body, a portion of its distal end being inserted into the tube body 20. The distal end portion of the inner tube 30 is housed inside the tube body 20 so as to be movable along the axis of the tube body 20. The proximal end portion of the inner tube 30 is led out from the tube body 20 and the housing 60 toward the proximal end side.

[0034] The inner tube 30 rotatably houses the shaft 50. The tip of the inner tube 30 is located on the base end side of the transducer unit 40, close to the transducer unit 40. The inner tube 30 is disposed between the inner circumferential surface of the tubular body 20 and the outer circumferential surface of the shaft 50, and stabilizes the movement of the shaft 50 in the rotational and axial directions.

[0035] The constituent materials of the tubular body 20 and the inner tube 30 are not particularly limited as long as they are flexible and have a certain degree of strength. For example, polyolefins such as polyethylene and polypropylene, polyesters such as polyamide and polyethylene terephthalate, fluorine-based polymers such as PTFE (polytetrafluoroethylene) and ETFE (ethylene-tetrafluoroethylene copolymer), PEEK (polyether ether ketone), polyimide, etc. can be suitably used.

[0036] The shaft 50 transmits the rotational force and the axial movement force acting from a drive unit (not shown) to the transducer unit 40. When the shaft 50 transmits the rotational power, the transducer unit 40 rotates, allowing 360-degree observation of the internal structure of tissue from blood vessels and cardiac cavities. The shaft 50 is also movable within the accommodation lumen 21 of the tubular body 20 along the axial center of the tubular body 20.

[0037] The proximal end of the tubular body 20 is fixed liquid-tight to the housing 60, which is provided with a first port 62 and a second port 64. The material of the housing 60 is not particularly limited as long as it has a certain degree of strength, but suitable materials for use include polycarbonate, polyamide, polysulfone, polyarylate, and methacrylate-butylene-styrene copolymer.

[0038] Ultrasonic scanning in the catheter 10 is performed by transmitting rotational motion to the shaft 50 and rotating the transducer unit 40 fixed to the tip of the shaft 50. This allows ultrasound waves transmitted and received by the ultrasound transducer 41 to scan in a substantially radial direction. Furthermore, by pulling the shaft 50 toward the proximal end, the ultrasound transducer 41 can be moved toward the proximal end while rotating. This makes it possible to obtain 360° cross-sectional images of the surrounding tissue of a blood vessel or a cardiac chamber in a scanning manner up to any position along the axis of the tubular body 20.

[0039] The catheter 10 according to this embodiment can be inserted into the right atrium HRa from the femoral vein Iv, as shown in FIG. 5, and used to observe the status of treatment by the treatment catheter 100.

[0040] A method for fixing the marker member 25 to the catheter 10 will be described. First, a covering portion 81 is prepared. As shown in FIG. 6, the covering portion 81 can be formed by dividing the tubular member 80 into multiple pieces in the circumferential direction. In FIG. 6, the tubular member 80 is divided into three pieces in the circumferential direction, but any number other than three may be used. This allows the covering portion 81 to have an arc-shaped cross section. The tubular member 80 has a longer length along the longitudinal direction of the tubular body 20 than the marker member 25. Furthermore, the covering portion 81 formed by dividing the tubular member 80 has a wider width along the circumferential direction of the tubular body 20 than the marker member 25. The covering portion 81 can be formed from the same material as the tubular body 20. The covering portion 81 has a wall thickness of 0.5 mm or more. By having the covering portion 81 have a certain thickness, the marker member 25 can be reliably pressed radially inward, allowing the marker member 25 to be embedded after welding. The covering portion 81 may be flat and not curved, but by making the cross section arc-shaped, it can be fitted along the outer periphery of the tubular main body 23 and can be welded smoothly.

[0041] As shown in FIG. 7, a marker member 25 is placed on the outer surface of the tubular body 23, and a covering portion 25 is placed around a portion of the tubular body 23 in the circumferential direction to cover the marker member 25. At this time, the marker member 25 is placed so as not to overlap the area where the outer peripheral welding surface 73 of the tip cap 22, which will be attached later, contacts the inner surface of the tubular body 23, so as to prevent interference between the welding interface 26 and the constricted portion 28 when welding the tip cap 22. Next, as shown in FIG. 8, a heat-shrinkable tube 85 is placed so as to cover the covering portion 25. The heat-shrinkable tube 85 shrinks radially when heated, allowing the inner materials to be welded together. The heat-shrinkable tube 85 may be a hollow member made of, for example, a fluororesin such as ETFE (ethylene-tetrafluoroethylene copolymer) or PTFE (polytetrafluoroethylene), a polyolefin such as PE (polyethylene) or PP (polypropylene), polyamide, polyester, or polyurethane.

[0042] The heat shrink tube 85 is provided so as to cover a wider area than the covering portion 81 that covers the marker member 25. Furthermore, the heat shrink tube 85 is provided so as not to overlap the area where the outer peripheral welding surface 73 of the tip cap 22, which will be attached later, comes into contact with the inner surface of the tubular body 23, in order to prevent interference with the welding interface 26 and the constricted portion 28 when welding the tip cap 22.

[0043] As shown in FIG. 9 , a core metal 87 is inserted into the lumen of the tubular body 23, and the heat-shrinkable tube 85 is heated. The heat-shrinkable tube 85 presses the inner covering portion 81 and the marker member 25 radially inward, welding the covering portion 81 to the tubular body 23. As a result, a welded interface 26 is formed around the marker member 25 in the tubular body 23, and the marker member 25 is embedded in the tubular body 20. Furthermore, the portion of the heat-shrinkable tube 85 located outside the covering portion 81 presses the outer surface of the tubular body 23 radially inward, forming a constricted portion 28 around the welded interface 26. The constricted portion 28 is formed to extend in the circumferential direction of the tubular body 20 to the opposite side of the protruding portion 27 across the center of the tubular body 23. The heat-shrinkable tube 85 is then removed.

[0044] In this way, by disposing and welding the covering portion 81 that covers the marker member to a portion of the circumferential direction of the tubular main body 23, it is possible to form a tubular body 20 with a reduced outer diameter.

[0045] Next, the tip cap 22 is fixed to the tubular body 20. The tip cap 22 is inserted from the tip surface of the tubular body 23 to which the marker member 25 is fixed. The surface of the tip cap 22 that comes into contact with the tubular body 23 is temporarily fixed with an adhesive. Then, as shown in Figure 10, a heat-shrinkable tube 86 is placed from the tip of the tubular body 23 to the tip cap 22. The tip cap 22 is welded to the tubular body 23 by heating the heat-shrinkable tube 86. The heat-shrinkable tube 86 is then removed. The marker member 25 is fixed in a position that does not interfere with the welding of the tip cap 22, so the tip cap 22 can be reliably fixed to the tubular body 20.

[0046] A modified example of the joining structure between the tubular body 23 and the marker member 25 will now be described. As shown in Fig. 11, the tubular body 23 may have a small diameter portion 90 in a part of its longitudinal direction, the small diameter portion having a smaller outer diameter than the other portions. The small diameter portion 90 can be formed by holding both sides of the tubular body 23 in the longitudinal direction with a jig and performing a pulling process. The small diameter portion 90 can also be formed by cutting the outside of the tubular body 23.

[0047] As shown in FIG. 12 , the marker member 25 is disposed in the small diameter portion 90. A covering portion 81 covering the marker member 25 and a heat-shrinkable tube 85 covering the covering portion 81 are also disposed in the small diameter portion 90. As a result, as shown in FIG. 13 , the marker member 25 is fixed to the small diameter portion 90, and a welded interface 91 between the tubular body 23 and the covering portion 81 is formed around the marker member 25. In this case, as shown in FIG. 14 , the outer surface of the tubular body 23 has a raised portion 92 that rises from the circular shape at a portion in the circumferential direction of the tubular body 23 at the small diameter portion 90 of the tubular body 23, which has a circular cross section when cut along a plane perpendicular to the longitudinal direction. Because the raised portion 92 is located in the small diameter portion 90, the outer diameter of the tubular body 20 can be made smaller.

[0048] 15, a part of the welding interface 93 between the tubular main body 23 and the covering portion 81 may be located outside the small diameter portion 90. This makes it possible to prevent kinking due to the small wall thickness at the tip portion of the tubular body 20. Note that the covering portion 81 may cover the tip of the small diameter portion 90.

[0049] 16, the tubular main body 23 may have a small diameter portion 95 in a part of its circumferential direction. The small diameter portion 95 is formed to have substantially the same width as the covering portion 81 that covers the marker member 25. This makes it possible to reduce the size of the outer diameter around the marker member 25 while ensuring the wall thickness of the tubular body 20.

[0050] As described above, the catheter 10 (1) according to this embodiment is a catheter 10 having a long tubular body 20, the tubular body 20 having a long tubular body 23 including a lumen, a marker member 25 disposed at the distal end of the tubular body 23 and including an inner surface 25a facing the center of the tubular body 23 and an outer surface 25b facing away from the inner surface 25a, and a covering portion 81 welded to the distal end of the tubular body 23 so as to cover only a portion of the circumference of the tubular body 23 together with the outer surface 25b of the marker member 25, and the weld interface 26 between the tubular body 23 and the covering portion 81 is disposed so as to surround the periphery of the marker member 25. In the catheter 10 configured in this manner, the covering portion 81 covers only a portion of the circumference of the tubular body 23, and therefore the outer diameter of the tubular body 20 can be reduced while the marker member 25 is covered by the covering portion 81. By reducing the outer diameter of the tubular body 20 of the catheter 10, the tubular body 20 is prevented from getting caught on the inner surface of the sheath used to insert the catheter 10 into the lumen of the living body, allowing the tubular body 20 to be inserted smoothly.

[0051] (2) In the catheter 10 described in (1) above, the distal end of the tubular body 23 may have a circular cross section taken along a plane perpendicular to the longitudinal direction, and the outer surface of the tubular body 20 may have a raised portion 27 formed by the covering portion 81 on a circumferential portion of the tubular body 20, the raised portion 27 being raised from the circular shape, and the welded interface 26 may be formed as a closed line along the periphery of the raised portion 27. As a result, the raised portion 27 is formed only on a circumferential portion of the tubular body 20, and the outer diameter of the tubular body 20 can be reduced. Furthermore, the welded interface 26 of the catheter 10 surrounds the entire circumference of the marker member 25, reliably preventing the marker member 25 from falling off the tubular body 20.

[0052] (3) In the catheter 10 described in (2) above, the outer surface of the tubular body 20 has a constricted portion 28 that surrounds at least the base end side of the protruding portion 27 and both sides in the circumferential direction of the tubular body 20, and extends to the opposite side of the protruding portion 27 and the center of the tubular body 23, and the constricted portion 28 may be recessed toward the center of the tubular body 23 more than the outer surface of the tubular body 20 near the base end of the constricted portion 28. This allows the outer diameter of the tubular body 20 of the catheter 10 to be smaller, making it easier to insert the catheter 10 into a sheath.

[0053] (4) In the catheter 10 of any of (1) to (3) above, the tubular body 23 has a distal opening communicating with the lumen, the tubular body 20 has a distal cap 22 that seals the distal opening of the tubular body 23, the distal cap 22 has an outer peripheral welding surface that is welded to the inner surface of the tubular body 23, and the distal end of the marker member 25 may be located proximally of the proximal end of the outer peripheral welding surface. This allows the catheter 10 to prevent the marker member 25 from interfering when the distal cap 22 is attached to the distal end of the tubular body 23.

[0054] (5) In the catheter 10 of any of (1) to (4) above, the tubular body 23 may have a small-diameter portion 90 at the tip end that has a smaller outer diameter than other portions, and the marker member 25 and the welded interface 26 may be disposed in the small-diameter portion 90. This allows the catheter 10 to further suppress an increase in the outer diameter of the tubular body 20 due to the marker member 25 and the covering portion 81.

[0055] (6) In the catheter 10 of any of (1) to (4) above, the tubular body 23 may have a small-diameter portion 90 at the tip end that has a smaller outer diameter than other portions, the marker member 25 is disposed in the small-diameter portion 90, and at least a portion of the welded interface 26 may be located outside the small-diameter portion 90. This allows the catheter 10 to suppress an increase in the outer diameter of the tubular body 20 due to the marker member 25 and the covering portion 81, while also suppressing kinking that occurs at the tip end of the tubular body 20.

[0056] The (7) method for fixing a marker member 25 to a catheter 10 according to this embodiment is a method for fixing a marker member 25 to a catheter 10 having a long tubular body 23 including a lumen, in which the marker member 25 is disposed on the outer surface of the distal end of the tubular body 23, a covering portion 81 is disposed on only a portion of the circumference of the tubular body 23 so as to cover the marker member 25, and the covering portion 81 is welded to the outer surface of the tubular body 23 to form a weld interface 26 that surrounds the periphery of the marker member 25. In this method for fixing the marker member 25 to the catheter 10, the covering portion 81 covers only a portion of the circumference of the tubular body 23, and therefore the outer diameter of the tubular body 20 can be reduced while the marker member 25 is covered by the covering portion 81.

[0057] The present invention is not limited to the above-described embodiment, and various modifications can be made by those skilled in the art within the technical concept of the present invention. [Explanation of symbols]

[0058] 10 Catheter 15 Sheath 20 Body 21 lumens 22 Tip cap 23 Tubular body 24 Bend 25 Marker material 25a Inner surface 25b External surface 26 Weld interface 27 Ridge 28 Neck 30 Inner tube 40 transducer unit 41 Ultrasonic vibrator 42 Vibrator holding part 50 shaft 60 Housing 70 Insertion section 73 Outer welding surface 80 Tubular member 81 Covering part

Claims

1. A catheter having a long tubular body, The tubular body has a long tubular main body including a lumen, a marker member disposed at a distal end of the tubular main body and including an inner surface facing the center of the tubular main body and an outer surface facing away from the inner surface, and a covering portion welded to the distal end of the tubular main body so as to cover only a portion of the circumferential direction of the tubular main body together with the outer surface of the marker member, A catheter in which the welded interface between the tubular body and the covering portion is arranged to surround the periphery of the marker member.

2. the distal end of the tubular body has a circular cross section taken along a plane perpendicular to the longitudinal axis; the outer surface of the pipe body has a protruding portion formed by the covering portion and protruding from the circular shape at a circumferential portion of the pipe body, The catheter according to claim 1 , wherein the weld interface is formed as a closed line along the periphery of the raised portion.

3. the outer surface of the tubular body has a constricted portion that surrounds at least a base end side of the protruding portion and both sides in the circumferential direction of the tubular body of the peripheral edge of the protruding portion, and extends to the opposite side of the protruding portion and the center of the tubular body, The catheter of claim 2 , wherein the constricted portion is recessed toward the center of the tubular body relative to the outer surface of the tubular body near the proximal end of the constricted portion.

4. the tubular body has a distal opening communicating with the lumen; the tubular body has a tip cap that seals the tip opening of the tubular body, the tip cap has an outer peripheral welding surface that is welded to the inner surface of the tubular body; The catheter according to any one of claims 1 to 3, wherein the tip of the marker member is located proximal to the proximal end of the outer peripheral welded surface.

5. the tubular body has a small diameter portion at the tip end, the small diameter portion having an outer diameter smaller than that of other portions; The catheter according to any one of claims 1 to 3, wherein the marker member and the welding interface are disposed in the small diameter portion.

6. the tubular body has a small diameter portion at the tip end, the small diameter portion having an outer diameter smaller than that of other portions; the marker member is disposed on the small diameter portion, The catheter according to any one of claims 1 to 3, wherein at least a portion of the welded interface is located outside the small diameter portion.

7. A method for fixing a marker member to a catheter having an elongated tubular body including a lumen, comprising: The marker member is disposed on an outer surface of the distal end of the tubular body; a covering portion is disposed on only a portion of the tubular body in a circumferential direction so as to cover the marker member; A method of securing a marker member to a catheter by welding the covering to the outer surface of the tubular body to form a welded interface that circumscribes the marker member.

Images