Dilator / catheter assembly and operation method of catheter assembly

Abstract

To provide a dilator capable of preventing a guiding catheter from easily coming off by improving backup force to the guiding catheter, a catheter assembly composed of the dilator, a guide extension catheter and the guiding catheter, and an operation method of the catheter assembly.SOLUTION: A dilator 10 includes a dilator distal tube 20 and a dilator linear shaft extending from the dilator distal tube 20 to a proximal side, where the dilator distal tube 20 has a proximal-side low lubrication part 24 and a distal-side high lubrication part 25. The dilator 10 is so configured that surface lubricity of the distal-side high lubrication part 25 is higher than that of the proximal-side low lubrication part 24, and a ratio of a length of the distal-side high lubrication part 25 to a whole length of the dilator end tube 20 is within a range of 10% to 70%.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a dilator that is inserted into a distal tube of a catheter having a distal tube on the distal end side and a linear shaft on the proximal end side, a catheter assembly including the dilator, a guide extension catheter, and a guiding catheter, and a method of operating the catheter assembly. [Background technology]

[0002] 2. Description of the Related Art A guiding catheter is used to guide a therapeutic catheter (such as a balloon catheter or a stent placement catheter) that is inserted into a biological lumen such as a blood vessel to perform treatment, diagnosis, or the like, to a target site.

[0003] For example, in percutaneous transluminal coronary angioplasty (PTCA), which is a treatment for the coronary artery, a guidewire for a guiding catheter is inserted into an artery through the skin of the wrist or thigh and reaches the entrance of the coronary artery. Next, the guiding catheter is inserted into the artery along the guidewire, and then the guidewire for the guiding catheter is removed and engaged with the coronary artery opening. A thinner guidewire for a treatment catheter is inserted into the lumen of the guiding catheter and passed through the lesion in the coronary artery. After this, a balloon catheter is inserted along the guidewire for the treatment catheter, the tip of the balloon catheter is protruded from the tip opening of the guiding catheter, and the balloon is advanced to the periphery in the coronary artery along the guidewire that has passed through the lesion, and the balloon is placed at the lesion and inflated to perform treatment.

[0004] In some cases, a guide extension catheter is used to smoothly advance a treatment catheter through a curved or bent coronary artery from the guiding catheter tip opening to the lesion after the tip of the guiding catheter is engaged with a predetermined site (e.g., the opening of a coronary artery). That is, a guide extension catheter can be inserted closer to the lesion than a guiding catheter, and can provide a stable backup force to the treatment catheter.

[0005] The guide extension catheter is a catheter having a so-called intermediate opening, which has a distal tube that can move through the lumen of the guiding catheter and protrude from the distal opening of the guiding catheter to the distal end side, and a linear shaft that is connected to the distal tube and extends from the distal tube to the proximal side, and the intermediate opening here is the proximal opening of the distal tube. Since the proximal side of the distal tube of the guide extension catheter is a linear shaft, the length of the tubular portion (distal tube) is short. Therefore, with a guidewire inserted inside the guiding catheter, the guide extension catheter can be easily inserted and removed from the guiding catheter along the guidewire without removing the guidewire.

[0006] When inserting a guide extension catheter into a guiding catheter and inserting its tip to the vicinity of a lesion, a dilator may be inserted into the lumen of the guide extension catheter to support passage through narrow or hard parts of the blood vessel. Inserting a guide extension catheter with a dilator inserted into its lumen into a blood vessel is disclosed in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2006-87643 A Summary of the Invention [Problem to be solved by the invention]

[0008] When inserting a guide extension catheter into a blood vessel, if there is a point where the guide extension catheter is difficult to pass through even when a dilator is inserted, the reaction force received by the guide extension catheter may cause the guiding catheter to become disengaged.

[0009] The present invention has been made to solve the above-mentioned problems, and has an object to provide a dilator that can improve the backup force for a guiding catheter and make the engagement of the guiding catheter less likely to come off, a catheter assembly consisting of a dilator, a guide extension catheter, and a guiding catheter, and a method of operating the catheter assembly. [Means for solving the problem]

[0010] A dilator that achieves the above-mentioned objective is a dilator having a dilator tip tube and a dilator linear shaft extending from the dilator tip tube toward the base end, wherein the dilator tip tube has a base end low-lubrication portion and a tip end high-lubrication portion, the tip end high-lubrication portion has a surface with higher lubricity than the base end low-lubrication portion, and the length of the tip end high-lubrication portion accounts for 10% to 70% of the total length of the dilator tip tube.

[0011] A catheter assembly that achieves the above-mentioned object is a catheter assembly comprising: a dilator having a dilator tip tube and a dilator linear shaft extending from the dilator tip tube toward the base end; a guide extension catheter having a tip tube and a linear shaft extending from the tip tube toward the base end; and a guiding catheter having an inner cavity through which the guide extension catheter is inserted, wherein the dilator tip tube is longer than the tip tube of the guide extension catheter, and when the dilator tip tube protrudes toward the tip end from the tip tube of the guide extension catheter, the ratio of the length of the part of the tip tube of the guide extension catheter protruding from the base end to the base end is in the range of 5% to 75% of the total length of the dilator tip tube, and a clearance calculated by subtracting the outer diameter of the linear shaft of the guide extension catheter and the outer diameter of the dilator tip tube from the diameter of the inner cavity of the guiding catheter is greater than 0 mm and less than 0.1 mm.

[0012] A method of operating a catheter assembly that achieves the above-mentioned objective is a method of operating a catheter assembly comprising: a dilator having a dilator tip tube and a dilator linear shaft extending from the dilator tip tube toward the base end; a guide extension catheter having a tip tube and a linear shaft extending from the tip tube toward the base end; and a guiding catheter having an inner lumen through which the guide extension catheter is inserted, the method including engaging a tip portion of the guiding catheter with an inlet of a coronary artery, and with the dilator tip tube protruding toward the tip side from the tip tube of the guide extension catheter, advancing the guide extension catheter toward the tip side from the tip of the guiding catheter, and moving the dilator tip tube toward the tip side relative to the tip tube of the guide extension catheter. Effect of the Invention

[0013] The dilator configured as described above, when its tip is protruded distally from the guide extension catheter, improves passage through the blood vessel due to the highly lubricating tip portion, while the friction coefficient is large when the base end contacts the inner surface of the guiding catheter, so that the backup force of the guide extension catheter can be increased. This makes it possible to prevent the guide extension catheter from being pushed back at a point in the blood vessel where it is difficult to pass, thereby preventing the guiding catheter from being released from its engagement with the living body.

[0014] The distal end high lubrication portion may have an intermediate lubrication portion having a surface lubricity higher than that of the proximal end low lubrication portion, and a distal end lubrication portion disposed distally of the intermediate lubrication portion and having a surface lubricity higher than that of the intermediate lubrication portion. This allows the lubricity to be increased stepwise along the length of the dilator distal end tube, and a certain degree of backup force to be generated in the intermediate lubrication portion.

[0015] In the catheter assembly configured as described above, the portion of the dilator tip tube that protrudes from the tip tube of the guide extension catheter toward the base end side comes into contact with the inner surface of the guiding catheter, and the small clearance at that portion allows the dilator to fully exert its backup force on the guide extension catheter. This makes it possible to prevent the guide extension catheter from being pushed back at a point in the blood vessel where it is difficult to pass, thereby preventing the guiding catheter from being released from its engagement with the living body.

[0016] The method of operating the catheter assembly configured as described above makes it easier to pass through places that are difficult to pass through with a guide extension catheter alone. [Brief description of the drawings]

[0017] [Figure 1] 1 is a plan view showing a dilator according to this embodiment, a guide extension catheter into which the dilator is inserted, and a guiding catheter into which the guide extension catheter is inserted. FIG. [Diagram 2] 1A to 1C are diagrams showing a guide extension catheter, in which (a) is a side view, (b) is a plan view, and (c) is an enlarged view of a portion of the linear shaft. [Diagram 3] 1A to 1C are diagrams showing a dilator, in which (a) is a side view, (b) is a plan view, and (c) is an enlarged view of a portion of the dilator linear shaft. [Figure 4] FIG. 2 is a side view of the dilator near the dilator tip tube. [Diagram 5] 1 is a cross-sectional view showing a state in which a guide extension catheter is inserted into a guiding catheter and a dilator is inserted into the guide extension catheter. FIG. [Figure 6] 1 is a cross-sectional view taken along a plane perpendicular to the axial direction, showing the relationship between the guiding catheter, the dilator tip tube, and the linear shaft of the guide extension catheter. [Figure 7]1 is an explanatory diagram showing a state in which the tip of a guiding catheter is engaged with the entrance of a coronary artery and a guide extension catheter and a dilator are inserted into the coronary artery. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the dimensional ratios in the drawings may be exaggerated for the sake of explanation and may differ from the actual ratios. In this specification, the side of the device that is inserted into the blood vessel is referred to as the "distal side" and the side that is operated is referred to as the "base side".

[0019] 1, the dilator 10 according to this embodiment is a device that is inserted into the lumen of the guide extension catheter 50 and provides rigidity to the guide extension catheter 50, thereby facilitating insertion to the distal end side. The guide extension catheter 50 with the dilator 10 inserted therein is inserted into a guiding catheter 100. A combination of the dilator 10, the guide extension catheter 50, and the guiding catheter 100 constitutes a catheter assembly.

[0020] The guide extension catheter 50 has a soft tip 60a at its distal end, is inserted into a guiding catheter 100 having a tip shaped to engage with a coronary artery, protrudes from a distal opening 101 of the guiding catheter 100, and is used to extend a tube for guiding a treatment catheter from the guiding catheter 100 to the distal side. When used in lower limb arteries or cerebral arteries other than the coronary arteries, the tip of the guiding catheter 100 does not need to be shaped.

[0021] As shown in FIGS. 1 and 2, the guide extension catheter 50 includes a tubular distal end tube 60 and a linear shaft 70 that is connected to the distal end tube 60 and extends from the distal end tube 60 toward the base end side.

[0022] The distal tube 60 can move through the lumen of the guiding catheter 100 and protrude from the distal opening 101 of the guiding catheter 100 to the distal side. This allows the distal tube 60 to provide a lumen continuous with the guiding catheter 100. That is, in the procedure, the distal tube 60 of the guide extension catheter 50 is inserted closer to the lesion than the guiding catheter 100, and can provide a stable backup force to the treatment catheter.

[0023] The distal tube 60 is a tube having a lumen penetrating from the distal end to the proximal end, and includes a tubular portion 61 disposed on the distal end side and a semi-tubular portion 62 disposed on the proximal end side of the tubular portion 61. The tubular portion 61 is formed in a circular tube shape by providing material in a range of 360 degrees in the circumferential direction. The semi-tubular portion 62 is formed in a half-pipe shape by providing material in a range of approximately 180 degrees in the circumferential direction. The angle range in which the material of the semi-tubular portion 62 is provided is not particularly limited as long as it is less than 360 degrees, and may be, for example, less than 180 degrees. The semi-tubular portion 62 may not be provided, and may have an opening cut obliquely. The axial length of the tubular portion 61 is not particularly limited, but is, for example, 200 mm to 400 mm, and is 250 mm in this embodiment. The axial length of the semi-tubular portion 62 is not particularly limited, but is, for example, 5 mm to 200 mm. The inner diameter of the tip tube 60 is not particularly limited, but is, for example, 1.3 mm to 1.5 mm. The outer diameter of the tip tube 60 is not particularly limited, but is, for example, 1.55 mm to 1.75 mm.

[0024] It is preferable that the rigidity of the distal tube 60 decreases stepwise or gradually from the base end side to the distal end side. As a result, the rigidity of the distal tube 60 decreases toward the distal end side, resulting in a flexible structure, which allows the distal end portion to be flexible while providing high pushability to the proximal end portion. The rigidity of the distal tube 60 does not have to change from the base end side to the distal end side. The distal tube 60 has a distal tip 60a at its most distal end, which is made of, for example, a flexible material.

[0025] The distal tube 60 has a reinforcing layer 64 inside. The reinforcing layer 64 is formed of a coil in which at least one wire is wound in a spiral shape, or a plurality of braids in which a plurality of wires are braided, in order to reinforce the tubular portion 61 of the distal tube 60. The coil or braid is formed of a wire made of a metal material such as stainless steel or tungsten wire, and the cross-sectional shape of the wire is a circle, ellipse, oval, rectangle, or the like, and the diameter, width, and thickness of the wire are not particularly limited and are set appropriately.

[0026] The inner layer (not shown) is a layer that forms the inner circumferential surface of the tubular portion 61 and the semi-tubular portion 62 of the distal tube 60. The inner layer is preferably made of a low-friction material so that the guide wire, the treatment catheter, the dilator 10, and the like can slide easily inside. Examples of low-friction materials include, but are not limited to, fluororesins such as PTFE (polytetrafluoroethylene) and PFA (tetrafluoroethylene-perfluoroalkoxyethylene copolymer) and silicone resins. The thickness of the inner layer is not particularly limited, but is, for example, 0.0001 mm to 0.1 mm, preferably 0.005 mm to 0.05 mm, and more preferably 0.01 mm to 0.03 mm.

[0027] The material of the distal tube 60 is not particularly limited, but examples thereof include various thermoplastic elastomers such as styrene-based, polyolefin-based, polyurethane-based, polyester-based, polyamide-based, polybutadiene-based, trans-polyisoprene-based, fluororubber-based, and chlorinated polyethylene-based, polyether ketone, and polyimide-based, and one or a combination of two or more of these (polymer alloy, polymer blend, laminate, etc.) can be used. Alternatively, among various elastomers, polyester elastomers, polyamide elastomers, etc. can be preferably used.

[0028] The linear shaft 70 is a flexible wire, which may be a round wire, flat wire, or arc wire, but is preferably a round wire, and is connected to the distal tube 60 and extends from the distal tube 60 to the base end. The linear shaft 70 includes a linear base portion 71 and a shaped distal end portion 72 that is disposed on the distal end side of the base portion 71. The base portion 71 does not need to be always linear because it is flexible and bends flexibly. The distal end portion 72 includes an intermediate straight portion 73 that extends from the base portion 71 to the distal end side, a semicircular portion 74 that is disposed on the distal end side of the intermediate straight portion 73, and a distal straight portion 75 that extends from the semicircular portion 74 to the side opposite to the side on which the intermediate straight portion 73 is disposed.

[0029] Semicircular portion 74 is bent at the base end of tubular portion 61, or semitubular portion 62, changing its direction by approximately 180 degrees so as to draw a substantially semicircular shape. Semicircular portion 74 is disposed at a position overlapping reinforcing layer 64 in the axial direction of tip tube 60. In other words, both semicircular portion 74 and reinforcing layer 64 are provided within a predetermined range in the axial direction of tip tube 60. Semicircular portion 74 does not need to have a constant radius of curvature, and may be a semiellipse or the direction of the semicircular portion may exceed 180 degrees, or conversely, may be less than 180 degrees.

[0030] The linear shaft 70 may be coated with a low-friction material on all or at least a part of the portion exposed to the outside so that it can slide with low friction against the inner wall surface of the guiding catheter 100. Examples of low-friction materials include, but are not limited to, fluororesin and silicone resin. The linear shaft 70 may be coated with a lubricating material on all or at least a part of the portion exposed to the outside in order to improve the sliding property against the inner wall surface of the guiding catheter 100, and may be provided with a tapered portion.

[0031] The tip of the linear shaft 70 is disposed at a position overlapping with the reinforcing layer 64 in the axial direction of the distal tube 60. This improves the pushing strength and pull-out strength of the guide extension catheter 50, but the tip of the linear shaft 70 and the reinforcing layer 64 do not have to overlap in the axial direction of the distal tube 60.

[0032] In this embodiment, the outer diameter of the linear shaft 70 is set to 0.5 mm. However, the outer diameter of the linear shaft 70 is not particularly limited, and can be set in the range of, for example, 0.05 mm to 1 mm. The length of the axial direction of the base 71 of the linear shaft 70 is not particularly limited, and is, for example, 1100 mm to 1300 mm. The material of the linear shaft 70 is not particularly limited, and for example, stainless steel, nickel-titanium alloy, etc. can be suitably used. In addition, the cross-sectional shape of the linear shaft 70 is not limited to a circle, and may be, for example, a rectangle, a square, an ellipse, etc., and may be a different shape depending on the part. The linear shaft 70 may have a depth marker at the base 71 that can be visually confirmed in order to grasp the insertion length into the guiding catheter 100.

[0033] As shown in Figures 1 and 3, the dilator 10 includes a tubular dilator tip tube 20 and a dilator linear shaft 30 that is connected to the dilator tip tube 20 and extends from the dilator tip tube 20 toward the base end.

[0034] The dilator tip tube 20 is a tubular body having a lumen penetrating from the tip to the base end, and is equipped with a tip tapered section 21 disposed on the tip side, and a tubular section 22 disposed on the base end side of the tip tapered section 21. The tip tapered section 21 tapers in diameter toward the tip side.

[0035] In this embodiment, the entire axial length of the dilator tip tube 20 is 300 mm. However, the length of the dilator tip tube 20 is not limited to this. In addition, the dilator tip tube 20 is longer than the dilator linear shaft 30. The dilator tip tube 20 is preferably flexible to a certain degree. For this reason, the constituent material of the dilator tip tube 20 may be, for example, various thermoplastic elastomers such as styrene-based, polyolefin-based, polyurethane-based, polyester-based, polyamide-based, polybutadiene-based, transpolyisoprene-based, fluororubber-based, and chlorinated polyethylene-based, polyether ketone, and polyimide-based, and one or more of these may be combined (polymer alloy, polymer blend, laminate, etc.). Alternatively, of the various elastomers, for example, polyurethane elastomer, polyester elastomer, polyamide elastomer, etc. may be preferably used. The dilator tip tube 20 may contain an X-impermeable material (contrast medium) in the material.

[0036] In this embodiment, the outer diameter of the dilator tip tube 20 is 1.23 mm. However, the outer diameter of the dilator tip tube 20 is not limited to this and can be set in the range of, for example, 1.0 mm to 1.4 mm.

[0037] The dilator tip tube 20 may be formed, for example, by insert molding with the dilator linear shaft 30 placed in a mold, or the dilator linear shaft 30 may be embedded in the dilator tip tube 20 by a heat shrink method.

[0038] As shown in FIG. 4, the dilator tip tube 20 is divided into two regions along the axial direction based on the presence or absence of surface lubricity. The base end side of the dilator tip tube 20 is a base end low lubrication section 24 with low surface lubricity, and the tip end side of the dilator tip tube 20 is a tip end high lubrication section 25 with higher surface lubricity than the base end low lubrication section 24. The tip end high lubrication section 25 is further divided into two regions. The base end side of the tip end high lubrication section 25 is an intermediate lubrication section 26 with higher surface lubricity than the base end low lubrication section 24, and the tip end side of the tip end high lubrication section 25 is a tip end lubrication section 27 with higher surface lubricity than the intermediate lubrication section 26. However, the tip end high lubrication section 25 may have the same lubricity over its entire length.

[0039] The difference in lubricity between the base end side low lubrication portion 24, the intermediate lubrication portion 26, and the tip lubrication portion 27 can be adjusted by the presence or absence of a lubricant applied to the surface of the dilator tip tube 20 and the thickness of the application. Examples of lubricants include copolymers of epoxy group-containing monomers such as glycidyl acrylate, glycidyl methacrylate, 3,4-epoxycyclohexylmethyl acrylate, 3,4-epoxycyclohexylmethyl methacrylate, β-methylglycidyl methacrylate, and allyl glycidyl ether with hydrophilic monomers such as N-methylacrylamide, N,N-dimethylacrylamide, and acrylamide; (co)polymers composed of the above hydrophilic monomers; cellulose-based polymeric substances such as hydroxypropyl cellulose and carboxymethyl cellulose; polysaccharides, polyvinyl alcohol, methyl vinyl ether-maleic anhydride copolymers, water-soluble polyamides, poly(2-hydroxyethyl (meth)acrylate), polyethylene glycol, polyacrylamide, and polyvinylpyrrolidone. Preferably, hydrophilic lubricating polymers such as polyacrylamide copolymers containing acrylamide can be used.

[0040] The base end low lubricated portion 24 and the tip end high lubricated portion 25 each occupy 50% of the total length of the dilator tip tube 20. Since the total length of the dilator tip tube 20 is 300 mm, the base end low lubricated portion 24 and the tip end high lubricated portion 25 each have a length of 150 mm. The tip end lubricated portion 27 of the tip end high lubricated portion 25 has a length of 100 mm, and the intermediate lubricated portion 26 has a length of 50 mm. However, the ratio of the length of the base end low lubricated portion 24 and the tip end high lubricated portion 25 to the total length of the dilator tip tube 20, and the ratio of the length of the tip end lubricated portion 27 and the intermediate lubricated portion 26 to the length of the tip end high lubricated portion 25 are not limited to this example. At least, the ratio of the length of the tip end high lubricated portion 25 to the total length of the dilator tip tube 20 is set in the range of 10% to 100%, more preferably in the range of 10% to 70%, and in this embodiment, it is 50%.

[0041] The portion of the dilator tip tube 20 that protrudes from the guide extension catheter 50 to the tip side has high lubricity due to the tip-side high lubricity portion 25, and can smoothly enter the blood vessel, improving passability. On the other hand, the portion of the dilator tip tube 20 located inside the guide extension catheter 50 or on the base end side of the guide extension catheter 50 has low lubricity due to the base-side low lubricity portion 24, and therefore has a high friction coefficient against the inner surface of the guide extension catheter 50 and the guiding catheter 100. This makes it easier to generate a backup force that counteracts the force received when the dilator tip tube 20 is advanced. This makes it difficult for the dilator 10 to move in the opposite direction to the advancement direction when the dilator tip tube 20 receives a force from a narrow or hard part in the blood vessel in the opposite direction to the advancement direction. This makes it difficult for the guiding catheter 100 to receive a force in the direction of withdrawal from the coronary artery entrance, and prevents the guiding catheter 100 from being withdrawn from the coronary artery entrance with which it is engaged.

[0042] The dilator linear shaft 30 is a flexible wire that is connected to the dilator tip tube 20 and extends from the dilator tip tube 20 to the base end side. The dilator linear shaft 30 includes a linear shaft base 31 and a shaft tip shape portion 32 that is arranged and shaped on the tip side of the shaft base 31. The shaft base 31 is flexible and bends flexibly, so it does not always need to be straight. The shaft tip shape portion 32 includes a shaft intermediate straight portion 33 that extends from the shaft base 31 to the tip side, a shaft semicircular portion 34 that is arranged on the tip side of the shaft intermediate straight portion 33, and a shaft tip straight portion 35 that extends from the shaft semicircular portion 34 to the side opposite to the side where the shaft intermediate straight portion 33 is provided. The dilator linear shaft 30 is connected to the dilator tip tube 20 after the shaft tip shape portion 32 is shaped into a predetermined shape.

[0043] The outer diameter of the dilator linear shaft 30 is not particularly limited, but is, for example, 0.05 mm to 1 mm. The material of the dilator linear shaft 30 is not particularly limited, but for example, stainless steel, nickel-titanium alloy, etc. can be suitably used. The cross-sectional shape of the dilator linear shaft 30 is not limited to a circle, but may be, for example, a rectangle, a square, an ellipse, etc., and may be a different shape depending on the part. The dilator linear shaft 30 may have a depth marker that can be visually confirmed in order to grasp the insertion length into the guiding catheter 100.

[0044] The guide extension catheter 50 and the dilator 10 can be used by inserting the dilator 10 into the guiding catheter 100, with the dilator 10 inserted into the guide extension catheter 50, as shown in Fig. 5. The guide extension catheter 50 and the dilator 10 may be packaged in an assembled state. This improves the convenience of the procedure, and the procedure can be performed immediately after opening the package.

[0045] The dilator tip tube 20 of the dilator 10 protrudes from the tip tube 60 of the guide extension catheter 50 to the tip side, and the base end protrudes from the base end of the tip tube 60 to the base end side. When the total length of the tip tube 60 of the guide extension catheter 50 is 250 mm, the total length of the dilator tip tube 20 is set to 900 mm. That is, the dilator tip tube 20 is formed longer than the tip tube 60 of the guide extension catheter 50. The base end of the dilator tip tube 20 is located on the base end side of the base end of the half tube portion 62 of the tip tube 60 of the guide extension catheter 50. When the dilator tip tube 20 protrudes from the tip tube 60 of the guide extension catheter 50 to the tip side, the ratio of the length of the part protruding from the base end of the tip tube 60 of the guide extension catheter 50 to the total length of the dilator tip tube 20 is set in the range of 5% to 70%, more preferably in the range of 55% to 70%. The state in which the dilator tip tube 20 protrudes from the tip tube 60 of the guide extension catheter 50 to the tip side is not particularly limited, but may be a state in which at least the tip taper portion 21 protrudes to the tip side, or a state in which at least the tip lubricated portion 27 protrudes to the tip side. Alternatively, when the base end of the dilator linear shaft 30 and the base end of the linear shaft 70 of the guide extension catheter 50 are aligned, the dilator tip tube 20 may be in a state in which it protrudes from the tip tube 60 of the guide extension catheter 50 to the tip side. In addition, the dilator tip tube 20 is longer than the dilator linear shaft 30. In addition, the dilator tip tube 20 may be provided with a highly lubricated portion, and a highly lubricated portion may be provided at least at the tip and over the entire length by applying a lubricant.

[0046] 6, the clearance calculated by subtracting the outer diameter of the linear shaft 70 of the guide extension catheter 50 and the outer diameter of the dilator tip tube 20 from the diameter of the lumen of the guiding catheter 100 is set to be very small. As described above, the outer diameter of the linear shaft 70 of the guide extension catheter 50 is 0.5 mm, and the outer diameter of the dilator tip tube 20 is 1.23 mm, and in this embodiment, the clearance C between them and the lumen of the guiding catheter 100 is set to 0.07 mm. However, the clearance C may be set to another value, and is set in a range of at least greater than 0 mm and less than 0.1 mm. This reduces the gap between the portion of the dilator tip tube 20 protruding toward the base end from the tip tube 60 of the guide extension catheter 50 and the inner surface of the guiding catheter 100, making it easier for the dilator tip tube 20 to exert a backup force due to friction between the guiding catheter 100 and the base end side of the dilator tip tube 20, i.e., the base end side of the dilator tip tube 20 exposed to the base end side from the base end opening in the tip tube 60 of the guide extension catheter 50 comes into contact with the inner surface of the guiding catheter 100.

[0047] Next, a method of using the catheter assembly including the dilator 10 of this embodiment will be described. Here, a method of delivering the tip of the guide extension catheter 50 to the vicinity of the lesion in the coronary artery S will be described.

[0048] Before inserting the guide extension catheter 50 into the blood vessel, the guiding catheter 100 is inserted into the blood vessel and engaged with the coronary artery entrance T. For this purpose, first, an introducer sheath (not shown) is percutaneously inserted into the blood vessel upstream (proximal end side) of the lesion of the blood vessel. The guidewire 80 is inserted into the blood vessel through the introducer sheath. Next, the guidewire 80 is pushed forward and reaches the proximal end side of the lesion. Thereafter, the proximal end of the guidewire 80 located outside the body is inserted into the distal end opening 101 of the guiding catheter 100. The guiding catheter 100 is inserted into the blood vessel along the guidewire 80, and as shown in FIG. 7, it reaches the coronary artery entrance T and engages with it.

[0049] Next, with the dilator 10 inserted into the lumen of the guide extension catheter 50, the proximal end of the guide wire 80 located outside the body is inserted into the distal end of the dilator distal tube 20, and the guide extension catheter 50 and the dilator 10 are pushed along the lumen of the guiding catheter 100. The surgeon projects the guide extension catheter 50 toward the distal end from the distal end of the guiding catheter 100 and pushes it through the coronary artery S until the distal end of the guide extension catheter 50 reaches the vicinity of the lesion. At this time, as shown in FIG. 7, the dilator distal tube 20 is pushed forward in a state where it projects toward the distal end from the distal tube 60 of the guide extension catheter 50. As described above, the distal end of the dilator distal tube 20 is a distal highly lubricated portion 25 that is hydrophilically coated, and can be smoothly inserted into the coronary artery S.

[0050] Since the clearance between the outer peripheral surface of the dilator tip tube 20 and the inner peripheral surface of the tip tube 60 is small, the outer peripheral surface of the dilator tip tube 20 and the inner peripheral surface of the tip tube 60 come into contact with each other on a small surface. Therefore, the dilator tip tube 20 plays a role in smoothly guiding the guide extension catheter 50 to the target position along the guide wire 80. The target position may be a position just before the lesion or beyond the lesion.

[0051] As described above, the portion of the dilator tip tube 20 located on the proximal side of the tip tube 60 of the guide extension catheter 50 is the proximal side low lubrication portion 24, which has low lubricity, and therefore has a high friction coefficient with respect to the inner surface of the guiding catheter 100. Therefore, even if the tip of the dilator tip tube 20 is subjected to a force pushing back by a narrow or hard part of the blood vessel, a backup force is exerted to prevent the guiding catheter 100 from moving, and the engagement state of the guiding catheter 100 with the coronary artery entrance T can be prevented from being released.

[0052] Furthermore, if there is a portion in the coronary artery S where it is difficult to advance the guide extension catheter 50, the surgeon attempts to advance only the dilator 10 while keeping the guide extension catheter 50 stationary in the axial direction. That is, the dilator tip tube 20 is moved toward the tip side relative to the tip tube 60 of the guide extension catheter 50. By advancing the guide extension catheter 50 along the dilator tip tube 20, it is possible to pass through a step or a calcified lesion that is difficult to pass through with the guide extension catheter 50 alone.

[0053] When the guide extension catheter 50 reaches the vicinity of the lesion, the surgeon fixes the position of the guidewire 80 and removes the dilator tip tube 20 from the guide extension catheter 50. Next, the treatment catheter is passed through the lumen of the guiding catheter 100 and the guide extension catheter 50 and along the guidewire 80 to reach the lesion. After this, the surgeon can treat the lesion (for example, dilate it with a balloon or place a stent) with the treatment catheter.

[0054] As described above, the dilator 10 according to the present embodiment has the dilator distal tube 20 and the dilator linear shaft extending from the dilator distal tube 20 to the base end side, the dilator distal tube 20 has the base end low lubrication portion 24 and the distal end high lubrication portion 25, the surface of the distal end high lubrication portion 25 has a higher lubricity than the base end low lubrication portion 24, and the proportion of the length of the distal end high lubrication portion 25 to the total length of the dilator distal tube 20 is in the range of 10% to 100%, more preferably 10% to 50%. When the distal end of the dilator 10 configured in this manner is projected distally from the guide extension catheter 50, the distal end high lubrication portion 25 improves passability through the blood vessel, while the friction coefficient when the proximal end contacts the inner surface of the guiding catheter 100 is large, so that the backup force of the guide extension catheter 50 can be increased. This makes it possible to prevent the guide extension catheter 50 from being pushed back at a location in the blood vessel that is difficult to pass through, thereby preventing the guiding catheter 100 from being released from its engagement with the living body.

[0055] In the catheter assembly, the clearance calculated by subtracting the outer diameter of the linear shaft 70 of the guide extension catheter 50 and the outer diameter of the dilator tip tube 20 from the diameter of the lumen of the guiding catheter 100 may be greater than 0 mm and smaller than 0.1 mm. The catheter assembly configured in this manner has a small clearance in that portion, allowing the dilator 10 to fully exert a backup force on the guide extension catheter 50. This makes it possible to prevent the guide extension catheter 50 from being pushed back at a portion of the blood vessel where it is difficult to pass, thereby preventing the guiding catheter 100 from being released from its engagement with the living body.

[0056] The distal end high lubrication portion 25 may have an intermediate lubrication portion 26 having a surface lubricity higher than that of the proximal end low lubrication portion 24, and a distal end lubrication portion 27 disposed distally of the intermediate lubrication portion 26 and having a surface lubricity higher than that of the intermediate lubrication portion 26. This allows the lubricity to be increased stepwise along the length of the dilator distal end tube 20, and a certain degree of backup force to be generated in the intermediate lubrication portion 26.

[0057] The catheter assembly according to the present embodiment is a catheter assembly including a dilator 10 having a dilator tip tube 20 and a dilator linear shaft 30 extending from the dilator tip tube 20 toward the base end side, a guide extension catheter 50 having a tip tube 60 and a linear shaft 70 extending from the tip tube 60 toward the base end side, and a guiding catheter 100 having an inner cavity through which the guide extension catheter 50 is inserted. The dilator tip tube 20 is longer than the tip tube 60 of the guide extension catheter 50 and is a dilator having a linear shaft 30 extending from the tip tube 20 toward the base end side. When the dilator tip tube 20 protrudes from the tip tube 60 of the guide extension catheter 50 to the tip side, the ratio of the length of the portion protruding from the base end of the tip tube 60 of the guide extension catheter 50 to the total length of the dilator tip tube 20 is in the range of 5% to 75%, preferably 55% to 70%, and the clearance calculated by subtracting the outer diameter of the linear shaft 70 of the guide extension catheter 50 and the outer diameter of the dilator tip tube 20 from the diameter of the lumen of the guiding catheter 100 is greater than 0 mm and smaller than 0.1 mm. In the catheter assembly thus configured, the portion of the dilator tip tube 20 protruding from the tip tube 60 of the guide extension catheter 50 to the base end side comes into contact with the inner surface of the guiding catheter 100, and the small clearance of this portion allows the dilator to fully exert its backup force on the guide extension catheter 50. This makes it possible to prevent the guide extension catheter 50 from being pushed back at a location in the blood vessel that is difficult to pass through, thereby preventing the guiding catheter 100 from being released from its engagement with the living body.

[0058] The method of operating the catheter assembly according to the present embodiment is a method of operating a catheter assembly including a dilator 10 having a dilator tip tube 20 and a dilator linear shaft 30 extending from the dilator tip tube 20 to the base end side, a guide extension catheter 50 having a tip tube 60 and a linear shaft 70 extending from the tip tube 60 to the base end side, and a guiding catheter 100 having an inner cavity through which the guide extension catheter 50 is inserted, in which the tip of the guiding catheter 100 is engaged with the inlet of the coronary artery, and in a state in which the dilator tip tube 20 protrudes from the tip tube 60 of the guide extension catheter 50 to the tip side, the guide extension catheter 50 is advanced from the tip of the guiding catheter 100 to the tip side, and the dilator tip tube 20 is moved toward the tip side relative to the tip tube 60 of the guide extension catheter 50. The method of operating the catheter assembly configured in this way makes it easier to pass through places where the guide extension catheter 50 alone has difficulty passing.

[0059] 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]

[0060] 10 Dilator 20 Dilator tip tube 21 Tapered tip 22 Cylindrical part 24 Proximal low lubrication section 25 Tip side highly lubricated part 26 Intermediate lubrication section 27 Tip lubrication section 30 Dilator linear shaft 50 Guide Extension Catheter 60 Tip Tube 70 Linear Shaft 80 Guidewire 100 Guiding catheter 101 Tip opening

Claims

1. A dilator having a dilator distal tube and a dilator linear shaft extending from the dilator distal tube to a proximal end side, The dilator tip tube has a base end low lubrication portion and a tip end high lubrication portion, the tip end high lubrication portion has a surface with higher lubricity than the base end low lubrication portion, and the length of the tip end high lubrication portion accounts for 10% to 70% of the total length of the dilator tip tube.

2. The dilator according to claim 1, wherein the tip side high lubrication portion has an intermediate lubrication portion having a surface lubricity higher than that of the base side low lubrication portion, and a tip side lubrication portion arranged distal to the intermediate lubrication portion and having a surface lubricity higher than that of the intermediate lubrication portion.

3. a dilator having a dilator distal tube and a dilator linear shaft extending from the dilator distal tube to a proximal end side; a guide extension catheter having a distal tube and a linear shaft extending from the distal tube to a proximal end side; A catheter assembly including a guiding catheter having an inner lumen through which the guide extension catheter is inserted, the dilator distal tube is longer than the distal tube of the guide extension catheter, and when the dilator distal tube protrudes from the distal tube of the guide extension catheter to the distal side, the length of the portion of the distal tube of the guide extension catheter protruding from the proximal end to the proximal side is in the range of 5% to 75% of the total length of the dilator distal tube; A catheter assembly in which a clearance calculated by subtracting the outer diameter of the linear shaft of the guide extension catheter and the outer diameter of the dilator tip tube from the diameter of the lumen of the guiding catheter is greater than 0 mm and smaller than 0.1 mm.

4. a dilator having a dilator distal tube and a dilator linear shaft extending from the dilator distal tube to a proximal end side; a guide extension catheter having a distal tube and a linear shaft extending from the distal tube to a proximal end side; A method for operating a catheter assembly including a guiding catheter having an inner lumen through which the guide extension catheter is inserted, comprising: Engage a distal end of the guiding catheter with an inlet of a coronary artery; With the dilator distal end tube protruding from the distal end tube of the guide extension catheter, the guide extension catheter is advanced from the distal end of the guiding catheter to the distal end side; A method of operating a catheter assembly, comprising: moving the dilator distal tube toward the distal end side relative to the distal tube of the guide extension catheter.

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