Dilator

Abstract

To provide a dilator with small sliding resistance against a valve element.SOLUTION: In a dilator 12 with a tubular long body 30, the long body 30 includes a base part 32 and a tip small-diameter part 33 extending to a tip side of the base part 32 and having an outer diameter smaller than that of the base part 32, and the base part 32 has a groove part 35 along a longitudinal direction. The tip small-diameter part 33 of the dilator 12 is formed in a tapered shape whose outer diameter decreases from the base part 32 side toward the tip side, and may have a length along the longitudinal axis of 50 mm-150 mm.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a dilator used when inserting a suction catheter for suctioning thrombi into a blood vessel. [Background technology]

[0002] Pulmonary embolism is a disease in which a blood clot blocks the pulmonary artery, causing breathing difficulties, etc., and requires treatment to remove the blood clot as soon as possible. A suction catheter with an outer diameter of about 5.3 mm to 8.0 mm is usually used to treat pulmonary embolism.

[0003] In order to support the insertion of the suction catheter into the blood vessel, a dilator is used which is inserted into the lumen of the suction catheter. The dilator is inserted from a hub provided at the base end of the suction catheter. For example, a dilator such as that shown in Patent Document 1 is known for insertion into the catheter. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-329063 A Summary of the Invention [Problem to be solved by the invention]

[0005] A valve is provided at the hub of the suction catheter to prevent blood from leaking out. The dilator inserted into the suction catheter slides against the valve when inserted and removed. The suction catheter used to treat pulmonary embolism has a large outer diameter, so the dilator also has a large outer diameter. For this reason, the dilator experiences a large resistance when sliding against the valve, and it can get stuck when inserted into or removed from the suction catheter.

[0006] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a dilator that has low sliding resistance against a valve body. [Means for solving the problem]

[0007] The dilator (1) according to the present invention which achieves the above-mentioned object is a dilator having a tubular elongated body, the elongated body having a base and a tip narrow diameter portion extending toward the tip side of the base and having an outer diameter smaller than that of the base, and the base has a groove portion along the longitudinal direction. Effect of the Invention

[0008] The dilator configured as described above can reduce the area of ​​sliding contact with the valve body due to the groove along the longitudinal direction, thereby reducing the sliding resistance against the valve body.

[0009] (2) In the dilator of (1) above, the tip narrow portion may be formed in a tapered shape with an outer diameter narrowing from the base side toward the tip side, and may have a length along the longitudinal direction of 50 mm to 150 mm. As a result, a tapered portion long in the longitudinal direction is formed at the tip of the dilator, so that the dimensional difference and physical property difference between the contrast catheter inserted into the dilator and the suction catheter inserted into the dilator change gradually along the longitudinal direction. Since the dimensional difference changes gradually along the longitudinal direction, the risk of damage to the vascular wall or thrombus detachment can be reduced when the dilator is inserted into a blood vessel together with the contrast catheter and the suction catheter. Furthermore, since the physical property difference changes gradually along the longitudinal direction, the deliverability can be improved when the dilator is combined with the contrast catheter and the suction catheter.

[0010] (3) In the dilator of (1) or (2) above, the groove may be provided in a plurality of grooves in the circumferential direction, and the ratio of the total circumferential width of the plurality of grooves to the circumference of the base may be 30% to 80%. This allows the dilator to sufficiently reduce sliding resistance when passing through the valve body.

[0011] (4) In any one of the dilators (1) to (3) above, the outer surface of at least the most distal end of the thin distal end portion may be smooth. This prevents the distal end of the dilator from becoming caught on the blood vessel wall when the dilator is inserted into the blood vessel by preventing unevenness at the distal end.

[0012] (5) In the dilator of any one of (1) to (4) above, the thin tip portion may have the groove portion in a portion closer to the base end than the most distal end portion, thereby reducing sliding resistance in a portion of the thin tip portion that has a large outer diameter.

[0013] (6) In the dilator of any one of (1) to (5) above, the long body may be inserted into a suction catheter having an outer diameter of 6.0 mm to 8.0 mm, so that the dilator can fully provide support when the suction catheter is inserted. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is an overall front view of an intravascular catheter and a dilator, and a suction catheter, which constitute a catheter assembly in this embodiment. [Diagram 2] FIG. 13 is a front view of the vicinity of the base end of a combination of a suction catheter, a dilator, an angiography catheter, and a guidewire. [Diagram 3] FIG. 2 is a front view of the vicinity of the tip portion of a combination of a suction catheter, a dilator, an angiography catheter, and a guidewire. [Figure 4] 1A and 1B are diagrams showing the tip of a contrast catheter, where (a) is a plan view, (b) is a view taken along the line B in (a), and (c) is a view taken along the line C in (a). [Diagram 5] 1A and 1B are cross-sectional views taken along a plane perpendicular to the longitudinal axis of the dilator, in which (a) is a cross-sectional view of the base, and (b) is a cross-sectional view of the tip. [Figure 6] 1 is a cross-sectional view of the vicinity of the tip of a combination of a suction catheter, a dilator, an angiography catheter, and a guidewire. FIG. [Figure 7]FIG. 13 is a partial cross-sectional view of the state in which the tip of the combination is inserted into the heart. [Figure 8] FIG. 2 is a cross-sectional view of an extruder for forming a long portion. [Figure 9] FIG. 2 is a perspective view of an in-die having a flight portion for use in an extruder. [Figure 10] FIG. 10 is a cross-sectional view of an extruder using the in-die of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that dimensions in the drawings may be exaggerated and may differ from actual dimensions for convenience of explanation. In addition, in this specification and the drawings, components having substantially the same functional configurations are given the same reference numerals to avoid duplicated explanation. In this specification, the side of the device that is inserted into the living body is referred to as the "distal side" and the side that is operated is referred to as the "base side".

[0016] The dilator 12 of the present embodiment is a medical device used in the treatment of pulmonary embolism, and is used when inserting into a blood vessel a suction catheter 13 that is inserted into the pulmonary artery to suction a thrombus. The dilator 12 is combined with an angiography catheter 11 to form a catheter assembly 10.

[0017] 1, the catheter assembly 10 has an angiography catheter 11 and a dilator 12. The angiography catheter 11 is inserted into the dilator 12, and the dilator 12 is inserted into the suction catheter 13.

[0018] The contrast catheter 11 has a long tubular shaft 20 and a hub 21 provided at the base end of the shaft 20. A tip portion 22 of the shaft 20 has a three-dimensional shape bent multiple times, but may have a flat shape bent once or a Judkins shape.

[0019] The dilator 12 has an elongated body 30 made of a long tubular member, and a hub 31 provided at the base end of the elongated body 30. The elongated body 30 has a base 32 having a constant outer diameter along the longitudinal direction, and a tip narrow-diameter section 33 at the tip of the dilator 12, the diameter of which decreases toward the tip. The tip narrow-diameter section 33 has an outer diameter smaller than that of the base 32 on the tip side of the base 32. The hub 31 of the dilator 12 has an insertion port 31a through which the contrast catheter 11 can be inserted, and a connection port 31b to which a device such as a syringe for injecting a contrast medium can be connected.

[0020] The suction catheter 13 has a long tubular suction shaft 40 and a hub 41 provided at the base end of the suction shaft 40. The hub 41 has an insertion port 41a through which the contrast catheter 11, the dilator 12, etc. are inserted, and a suction port 41b for connecting a device for suction. In addition, a valve body 41c is provided inside the hub 41, through which the inserted device passes and which prevents the outflow of fluid from the suction shaft 40 side.

[0021] Each of the tubes of the contrast catheter 11, the dilator 12, and the suction catheter 13 is formed so as to have an outer layer on the outside of an inner layer having a lumen. The inner layer is preferably formed of a low-friction material so that the guide wire 14 can slide easily inside. The low-friction material is, for example, fluororesin such as PTFE (polytetrafluoroethylene) and PFA (tetrafluoroethylene-perfluoroalkoxyethylene copolymer) or silicone resin, but is not limited thereto. The material constituting the outer layer is not particularly limited, but examples thereof include polystyrene, polyolefin, polyurethane, polyester, polyamide, styrene-based, polyolefin-based, polyurethane-based, polyester-based, polyamide-based, polybutadiene-based, transpolyisoprene-based, fluororubber-based, chlorinated polyethylene-based, and other thermoplastic elastomers, polyether ketone, polyimide-based, and the like, 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 elastomer, polyamide elastomer, etc. can be preferably used. Each tube may also have a reinforcing layer made of a braid between the inner layer and the outer layer.

[0022] 2, the shaft 20 of the angiography catheter 11 is inserted into the lumen of the dilator 12, and the angiography catheter 11 and the dilator 12 form a catheter assembly 10. The catheter assembly 10 is inserted into the inside of the suction catheter 13 through an insertion port 41a of the hub 41 of the suction catheter 13. In addition, a guidewire 14 is inserted into the angiography catheter 11 from the hub 21 to the shaft 20.

[0023] 3, the tip of the dilator 12 is exposed distally beyond the tip of the suction shaft 40. The tip 22 of the angiography catheter 11 is exposed distally beyond the tip of the dilator 12. The guidewire 14 protrudes distally beyond the tip of the angiography catheter 11.

[0024] As shown in Figures 4(a) to (c), the tip portion 22 has a base curved portion 22a, a base straight portion 22b, an intermediate curved portion 22c, an intermediate straight portion 22d, a tip curved portion 22e, and a most distal portion 22f.

[0025] The base curved portion 22a extends from the tip of the base portion 23, which is closer to the base end than the tip portion 22, toward the tip side, and is curved within a plane. The base straight portion 22b extends from the tip of the base curved portion 22a in a substantially straight line toward the tip side. The middle curved portion 22c extends from the tip of the base straight portion 22b toward the tip side, and is curved within a plane. The middle curved portion 22c is curved in a direction different from the bending direction of the base curved portion 22a. The middle straight portion 22d extends from the tip of the middle curved portion 22c in a substantially straight line toward the tip side. The tip curved portion 22e extends from the tip of the middle straight portion 22d toward the tip side, and is curved within a plane. The most distal portion 22f extends from the tip of the tip curved portion 22e in a substantially straight line toward the tip side. The lumen of the shaft 20 opens at the tip of the most distal portion 22f. The axis of the most distal portion 22f is not located on an extension of the axis of the intermediate straight portion 22d.

[0026] The angle α1 that base straight portion 22b makes with respect to an extension line extending from the tip side part of base 23 toward the tip side is greater than 0° and less than 90°, and is preferably 40° to 85°, and more preferably 40° to 80°. When angle α1 is less than 90°, it can be easily inserted into a curved path from inside the heart toward the pulmonary artery, and a pushing force can be easily transmitted to the tip side.

[0027] The angle α2 that the intermediate straight portion 22d makes with respect to an extension line extending from the base straight portion 22b toward the tip is not particularly limited, but is approximately parallel or exceeds 0° and is less than 180°, is preferably 100° to 175°, and is more preferably 110° to 170°.

[0028] The angle α3 that the most distal portion 22f makes with respect to an extension line extending from the intermediate straight portion 22d toward the tip direction is not particularly limited, but is greater than 0° and less than 180°, preferably 5° to 80°, and more preferably 10° to 60°. The most distal portion 22f is not positioned coaxially with the intermediate straight portion 22d.

[0029] The axis centers of the tip side portion of the base 23, the base curved portion 22a and the base straight portion 22b, are located on the first plane P1. The axis centers of the intermediate curved portion 22c and the intermediate straight portion 22d are located on the second plane P2. The axis centers of the tip curved portion 22e and the most distal portion 22f are located on the third plane P3. The axis center of the base straight portion 22b located on the first plane P1 may also be located on the second plane P2. The axis center of the intermediate straight portion 22d located on the second plane P2 may also be located on the third plane P3.

[0030] The second plane P2 is a plane different from the first plane P1. The angle β of the second plane P2 with respect to the first plane P1 on the distal side of the base curved portion 22a is more than 0° and less than 180°, preferably 30° to 150°, and more preferably 80° to 100°. Since the second plane P2 is different from the first plane P1, the shaped portion 24 having the base curved portion 22a and the intermediate curved portion 22c can have a twisted shape that draws a three-dimensional spiral. Therefore, the distal end portion 22 of the shaft 20 is easily aligned with the inner wall surface of the blood vessel, and the posture within the blood vessel is easily stabilized. In addition, when the proximal end portion of the contrast catheter 11 is rotated in the direction in which the contrast catheter 11 is wound toward the distal end side, the rotational force is efficiently transmitted to the distal end side, making it easy to push the contrast catheter 11 toward the distal end.

[0031] The third plane P3 is a plane different from the first plane P1 and the second plane P2. The third plane P3 may coincide with the second plane P2, but it is preferable that the third plane P3 does not coincide with the second plane P2. By not coinciding the third plane P3 with the second plane P2, the opening of the most distal portion 22f can be oriented in a direction different from the curvature of the intermediate curved portion 22c.

[0032] In this embodiment, the distal curved portion 22e is bent from the base end side toward the tip end side away from the first plane P1. Therefore, the most distal end portion 22f extends from the base end side toward the tip opening 31 so as to move away from the first plane P1. The distal curved portion 22e is bent from the base end side toward the tip end side toward the opposite side of the side where the base portion 23 is located with respect to the second plane P2. Therefore, the most distal end portion 22f extends from the base end side toward the tip opening 31 toward the opposite side of the side where the base portion 23 is located with respect to the second plane P2. The distal curved portion 22e may be bent from the base end side toward the tip end side toward the side approaching the first plane P1. The distal curved portion 22e may be bent from the base end side toward the tip end side on a plane parallel to the first plane P1. The distal curved portion 22e may be bent from the base end side toward the tip end side toward the opposite side of the side where the base portion 23 is located from the second plane P2.

[0033] It should be noted that base straight portion 22b, intermediate straight portion 22d and tip end portion 22f need only be substantially straight and do not have to be formed as strictly straight lines.

[0034] If the minimum radius of curvature at the base curved portion 22a is R1, the minimum radius of curvature at the middle curved portion 22c is R2, and the minimum radius of curvature at the tip curved portion 22e is R3, then R1>R2>R3 is satisfied. That is, R2 is smaller than R1, and R3 is smaller than R2. The minimum radius of curvature is the radius of curvature of the portion with the smallest radius of curvature among the curved portions.

[0035] As shown in FIG. 1, the long body 30 of the dilator 12 has a plurality of grooves 35 along the long axis direction. The grooves 35 are continuously formed over the entire length of the base 32 of the long body 30 and over the portion of the tip thin-diameter portion 33 on the base 32 side. The grooves 35 are not formed in the most distal end portion 33a, which is the tip side portion of the tip thin-diameter portion 33. As shown in FIG. 5(a), the grooves 35 have a shape in which the surface of the long body 30 is recessed in a concave shape. However, the grooves 35 may be shallower than shown in FIG. The edges 35a of the grooves 35 on both sides in the width direction are rounded. Eight grooves 35 are formed along the circumferential direction of the base 32, and when the width of the grooves 35 along the circumferential direction is H, the total circumferential width of the grooves 35 is 8H. The ratio of the total width 8H of the grooves 35 to the circumference of the base 32 is 30% to 80%. As shown in FIG. 5(b), the most distal portion 33a of the dilator 12, which has a smaller outer diameter than the base portion 32, has a smooth outer surface.

[0036] As shown in FIG. 6, the dilator 12 is inserted into the lumen 43 of the suction catheter 13, and the angiography catheter 11 is inserted into the lumen 34 of the dilator 12. The guidewire 14 has an outer diameter D1 of 0.7 mm to 0.9 mm. The angiography catheter 11 has an inner diameter D2 of 0.9 mm to 1.3 mm, and an outer diameter D3 of the angiography catheter 11 of 1.4 mm to 2.0 mm. The dilator 12 has an inner diameter D4 of 1.4 mm to 2.5 mm at the most distal end of the thin-tip portion 33, and an outer diameter D5 of 1.7 mm to 2.6 mm. The dilator 12 has an outer diameter D6 of 5.3 mm to 6.8 mm at the base portion 32 on the proximal side of the thin-tip portion 33. The dilator 12 has the same inner diameter D6 from the base portion 32 to the thin-tip portion 33. The inner diameter D7 of the suction catheter 13 is 5.5 mm to 7.0 mm, and the outer diameter D8 of the suction catheter 13 is 6.0 mm to 8.0 mm.

[0037] The length of the tip narrow portion 33 of the dilator 12 along the longitudinal direction is 50 mm to 150 mm. Since the tip narrow portion 33 is long in the longitudinal direction, the dimensional difference and physical property difference between the dilator 12, the contrast catheter 11 inserted inside the dilator 12, and the suction catheter 13 through which the dilator 12 is inserted change gradually along the longitudinal direction. Since the dimensional difference changes gradually along the longitudinal direction, the risk of damage to the blood vessel wall or thrombus detachment can be reduced when the catheter assembly 10 and the suction catheter 13 are inserted into a blood vessel. Furthermore, since the physical property difference changes gradually along the longitudinal direction, the deliverability can be improved when the catheter assembly 10 and the suction catheter 13 are combined.

[0038] The clearance between the angiography catheter 11 and the dilator 12 is preferably 0.1 mm or more. This allows the contrast medium to be injected using the space between the angiography catheter 11 and the dilator 12 without removing the guide wire 14 when the catheter assembly 10 and the suction catheter 13 are combined and inserted into a blood vessel.

[0039] The long portion 30 of the dilator 12 having the groove portion 35 can be formed by a resin extrusion molding machine 200 shown in FIG. 8. The extrusion molding machine 200 arranges and fixes an in-die 220 and an out-die 225 in a housing 210, and forms a resin flow path 202 including a resin inlet 203 and a resin outlet 204. The extrusion molding machine 200 can form a tubular long portion 30 having the groove portion 35 by having a straightening section 206, which is a spider that divides the resin flow, in the upstream portion of the flow path 202 and a merging section 207 in the downstream portion of the flow path 202. Alternatively, as shown in FIG. 9, the in-die 220 may have a plurality of wing portions 223, which are spiders that divide the resin flow in the circumferential direction, in the circumferential direction. In this case, as shown in FIG. 10, the resin is diverted in the circumferential direction by the straightening section 206, divided in the circumferential direction by the wing portion 223, and merged at the merging section 207. The resin that joins at the joining portion 207 is divided by the blade portion 223 and combines with the resin that flows from the circumferentially adjacent position, but by adjusting the material of the resin and the flow speed, it is possible to pass through the flow path 202 while leaving a concave shape on the outer surface. In this way, the long portion 30 that is formed by passing through the flow path 202 can have a groove portion 35 formed along the long axis direction. By covering the core wire 226 with resin, it becomes easy to control the inner and outer diameters, and during extrusion molding, the groove portion 35 is formed over the entire length of the long portion 30, including the most distal end 33a. The outer surface of the most distal end 33a may be smoothed by heat treatment after extrusion molding.

[0040] Next, there will be described a treatment method using the catheter assembly 10 and the suction catheter 13 of this embodiment. The catheter assembly 10 and the suction catheter 13 are used for treating pulmonary embolism.

[0041] The contrast catheter 11 is first inserted through the dilator 12 to form the catheter assembly 10. The catheter assembly 10 is formed by inserting the shaft 20 of the contrast catheter 11 through the lumen 34 of the dilator 12 and leaving the tip of the shaft 20 exposed on the tip side beyond the tip of the dilator 12.

[0042] Also, the catheter assembly 10 is inserted into the lumen 43 of the suction catheter 13. The tip of the catheter assembly 10 is exposed distally beyond the tip of the suction catheter 13. Furthermore, the guidewire 14 is inserted into the angiography catheter 11, and the tip of the guidewire 14 is exposed distally beyond the tip of the angiography catheter 11.

[0043] When the catheter assembly 10 is inserted into the suction catheter 13, the dilator 12 constituting the catheter assembly 10 passes through the valve body 41c provided in the hub 41 of the suction catheter 13. Since the groove portion 35 is formed along the longitudinal direction in the long body 30 of the dilator 12 as described above, the contact area with the valve body 41c during passage can be reduced. This reduces the sliding resistance of the valve body 41c of the dilator 12, making it easier to insert the dilator 12 into the suction catheter 13.

[0044] The groove 35 is formed over the entire length of the base 32 of the dilator 12 and in a portion other than the most distal end 33a of the tip thin-diameter portion 33. The most distal end of the dilator 12 has a small diameter and can be easily inserted into the valve body 41c, and the groove 35 makes it easy to insert the other portion into the valve body 41c.

[0045] When inserting the catheter assembly 10 and the suction catheter 13 into a blood vessel, first, an insertion path into the blood vessel is secured. To do this, the surgeon percutaneously passes an introducer sheath (not shown) through the femoral vein. The surgeon inserts the combination of the guide wire 14, the catheter assembly 10, and the suction catheter 13 into the vein through this introducer sheath, and then advances the catheter assembly 10 and the suction catheter 13 while leading the guide wire 14.

[0046] Since the dilator 12 has a groove portion 35, a small gap occurs between the valve body 41c and the outer surface of the elongated body 30. However, since the catheter assembly 10 and the suction catheter 13 of this embodiment are inserted into a vein, blood leakage from the valve body 41c can be kept to a minimum.

[0047] 7, the contrast catheter 11 enters the right atrium 103 of the heart 100 from the inferior vena cava 101, passes through the right ventricle 104, and heads toward the pulmonary artery. Because the tip 22 of the contrast catheter 11 has the three-dimensional shape described above, the surgeon can easily push it through the curved path within the heart 100. The surgeon can push the suction catheter 13 together with the dilator 12 and the contrast catheter 11 through the blood vessels and reach the pulmonary artery.

[0048] If contrast is required during insertion of the suction catheter 13, the surgeon can connect a device for injecting a contrast medium, such as a syringe, to the hub 31 of the dilator 12 and inject the contrast medium using the space between the contrast catheter 11 and the dilator 12. This allows the injection of the contrast medium without removing the guidewire 14, simplifying the procedure.

[0049] Once the suction catheter 13 has reached the affected area of ​​the pulmonary artery, the surgeon removes the dilator 12, the contrast catheter 11, and the guidewire 14. Next, the surgeon connects a suction device to the suction port 41b provided in the hub 41 of the suction catheter 13, and starts suctioning the thrombus.

[0050] After the thrombus has been aspirated, the surgeon removes the suction catheter 13 from the blood vessel, completing the procedure.

[0051] As described above, the dilator 12 (1) according to this embodiment is a dilator 12 having a tubular long body 30, the long body 30 having a base 32 and a tip narrow diameter portion 33 extending to the tip side of the base 32 and having an outer diameter smaller than that of the base 32, and the base 32 has a groove portion 35 along the longitudinal direction. The dilator 12 thus configured can reduce the area in sliding contact with the valve body 41c due to the groove portion 35 along the longitudinal direction, and therefore can reduce the sliding resistance against the valve body 41c.

[0052] (2) In the dilator 12 described above in (1), the tip narrow portion 33 may be formed in a tapered shape with an outer diameter narrowing from the base portion 32 side toward the tip side, and the length along the longitudinal direction may be 50 mm to 150 mm. As a result, a tapered portion long in the longitudinal direction is formed at the tip of the dilator 12, so that the dimensional difference and physical property difference between the contrast catheter 11 inserted into the dilator 12 and the suction catheter 13 inserted into the dilator 12 change gradually along the longitudinal direction. Since the dimensional difference changes gradually along the longitudinal direction, the risk of damage to the vascular wall or thrombus detachment can be reduced when the dilator 12 is inserted into a blood vessel together with the contrast catheter 11 and the suction catheter 13. In addition, since the physical property difference changes gradually along the longitudinal direction, the deliverability can be improved when the dilator 12 is combined with the contrast catheter 11 and the suction catheter 13.

[0053] (3) In the dilator 12 of (1) or (2) above, a plurality of grooves 35 may be provided in the circumferential direction, and the ratio of the total circumferential width of the plurality of grooves 35 to the circumference of the base 32 may be 30% to 80%. This allows the dilator 12 to have a sufficiently small sliding resistance when passing through the valve body 41c.

[0054] (4) In the dilator 12 of any one of (1) to (3) above, at least the outer surface of the most distal end portion 33a of the thin distal end portion 33 may be smooth. This makes it possible to prevent the distal end of the dilator 12 from becoming uneven, thereby preventing the distal end from getting caught on the blood vessel wall when inserted into the blood vessel.

[0055] (5) In the dilator 12 of any one of (1) to (4) above, the tip thin portion 33 may have a groove 35 in a portion closer to the base end than the most distal end 33a. This can reduce the sliding resistance of the portion of the tip thin portion 33 that has a large outer diameter.

[0056] (6) In the dilator 12 of any one of (1) to (5) above, the long body 30 may be inserted into a suction catheter 13 having an outer diameter of 6.0 mm to 8.0 mm. This allows the dilator 12 to fully provide support when the suction catheter 13 is inserted.

[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 assembly 11 Contrast Catheter 12 Dilator 13 Suction catheter 14 Guidewire 20 Shaft 21 Hub 22 Tip 23 Base 24 lumen 30 Long body 31 Hub 32 Base 33 Thin tip 33a Cutting edge part 34 Lumen 35 Groove 35a Edge 40 Suction shaft 41 Hub 43 Lumen

Claims

1. A dilator having a tubular elongated body, The elongated body has a base portion and a tip portion having a smaller outer diameter than the base portion and extending toward a tip side of the base portion, The base portion of the dilator has a groove along the longitudinal direction.

2. 2. The dilator according to claim 1, wherein the tip thin portion is tapered so that the outer diameter becomes smaller from the base side to the tip side, and the length along the longitudinal axis is 50 mm to 150 mm.

3. The dilator according to claim 1, wherein the groove portions are provided in a circumferential direction, and a ratio of a total circumferential width of the groove portions to a circumference of the base portion is 30% to 80%.

4. The dilator according to claim 1 , wherein at least the outer surface of the most distal end of the thin tip portion is smooth.

5. The dilator according to claim 5 , wherein the tip thin portion has the groove portion at a portion closer to the base end than the most distal end portion.

6. The dilator according to any one of claims 1 to 5, wherein the elongated body is inserted into a suction catheter having an outer diameter of 6.0 mm to 8.0 mm.

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