Catheter assembly

Abstract

[Problem] To provide a catheter assembly enabling a dilator body to have high trackability over a guide wire and good insertability into a body lumen (reduced insertion resistance of the dilator body at the time of insertion into a body lumen) even when the dilator body has a large diameter. [Solution] In a state where a dilator body 100 is placed through a lumen 315 of a catheter body 310, a distal region 110 of the dilator body 100 is protruded distally from a distal end of the catheter body 310. The dilator body includes a foamed resin part 140 containing a fine bubble group 145 inside a wall 106 of the dilator body and extending across the boundary between a proximal end of the distal region and a distal end of an intermediate region 130.

Description

Catheter Assembly

[0001] The present invention relates to a catheter assembly.

[0002] Catheter assemblies such as introducers used in treatment, diagnosis, etc. using various medical devices are known. The catheter assemblies include a catheter with a tubular catheter body (e.g., an introducer sheath or a guiding sheath) and a dilator with a dilator body (dilator tube) inserted into the lumen of the catheter body (see, for example, Patent Document 1).

[0003] In a procedure using the catheter assembly described above, prior to inserting the catheter body into a biological lumen, the surgeon forms a perforation in the living body connecting the biological lumen to the outside of the living body and places a guidewire through this perforation between the biological lumen and the outside of the living body. The surgeon then inserts the dilator body into the catheter body, and with the catheter and dilator assembled, inserts the guidewire into the dilator body and inserts the dilator body and catheter body into the biological lumen along the guidewire. The surgeon then removes the dilator body from the catheter body while the catheter body remains inserted into the biological lumen. With the dilator body removed from the catheter body, the surgeon can use the lumen of the catheter body as an access path connecting the biological lumen to the outside of the living body to insert various medical devices used for treatment and diagnosis into the biological lumen.

[0004] By inserting the catheter assembly into a perforation formed in the living body with the dilator body inserted into the catheter body as described above, the surgeon can widen the perforation while preventing the dilator body from bending the catheter body.

[0005] The dilator body is required to have the ability to follow the guidewire inserted into the biological lumen prior to the catheter body, and to have insertability that can reduce the burden on the surgeon when operating the dilator.

[0006] Meanwhile, in recent years, attempts have been made to develop catheter assemblies intended for use in relatively large blood vessels such as arteries in the lower limbs (see, for example, Patent Document 2).

[0007] JP-A-7-303703 JP-A-2022-27860

[0008] The dilator included in the catheter assembly described in Patent Document 2 is larger than dilators intended for use in relatively thin blood vessels such as those in the upper limbs, etc. Therefore, the dilator body included in the dilator is also configured to have a large diameter corresponding to the diameter of the blood vessel into which it is to be inserted.

[0009] When the dilator body is configured with a large diameter, the amount of material (e.g., resin) that makes up the wall thickness of the dilator body (the portion that forms the tube wall) also increases. This increases the rigidity of the tip of the dilator body, leading to a decrease in the dilator body's ability to follow the guidewire. Furthermore, the increased amount of material that makes up the wall thickness of the tip of the dilator body also increases the insertion load of the dilator body.

[0010] Therefore, in catheter assemblies intended for use in relatively large blood vessels such as the arteries of the lower limbs, it becomes even more difficult to achieve the followability of the dilator body relative to the guidewire and high insertability of the catheter assembly into the body lumen.

[0011] The present invention has been made in consideration of the above problems, and aims to provide a catheter assembly that can achieve high followability of the dilator body relative to the guide wire and high insertability of the catheter assembly into a biological lumen (reduced insertion resistance of the dilator body when inserted into a biological lumen), even when the dilator body is configured with a large diameter.

[0012] The present invention can be achieved by any one of the following means (1) to (9).

[0013] (1) A catheter assembly comprising: a dilator comprising: a dilator body having a lumen penetrating between its distal end and proximal end; and a dilator hub connected to the proximal end of the dilator body and having an opening communicating with the lumen of the dilator body; and a catheter body having a lumen into which the dilator body can be inserted; and a catheter hub connected to the proximal end of the catheter body and connectable to the dilator hub, wherein the dilator body has a distal region, a proximal region, and an intermediate region located between the distal region and the proximal region, and the distal region is configured as a region that protrudes distally beyond the distal end of the catheter body when the dilator body is inserted through the lumen of the catheter body, and the dilator body has a foamed resin portion containing fine bubbles within the wall thickness of the dilator body so as to straddle the boundary between the proximal end of the distal region and the distal end of the intermediate region.

[0014] (2) The catheter assembly described in (1), wherein the distal region has a main body portion having an outer diameter substantially the same as the outer diameter of the intermediate region, and a tapered portion extending from the distal end of the main body portion toward the distal side and having an outer diameter that decreases from the base end toward the distal side, and the foamed resin portion is located so as to straddle the boundary between the distal end of the main body portion and the base end of the tapered portion, and the distal end of the foamed resin portion is located distally of the base end of the tapered portion.

[0015] (3) The catheter assembly according to (2), wherein the dilator body further has a non-foamed resin portion that does not contain the fine bubbles inside the thickness of the dilator body, and the non-foamed resin portion is located in a region between the tip of the tip region and the tip of the foamed resin portion, and in a region between the base end of the foamed resin portion and the base end of the dilator body, in the longitudinal direction of the dilator body.

[0016] (4) The catheter assembly according to (3), wherein the tip of the foamed resin portion is located closer to the base end than the center of the tapered portion.

[0017] (5) The catheter assembly according to any one of (1) to (4), wherein the catheter body has a first region and a second region located on the proximal side of the first region and having a reinforcing member inside the thickness of the catheter body, the first region does not have the reinforcing member, and the proximal end of the foamed resin portion is located in the second region when the dilator body is inserted through the lumen of the catheter body.

[0018] (6) The catheter assembly according to (4) or (5), wherein the cross-sectional area of ​​the wall thickness of the dilator body at a position in the main body corresponding to the foamed resin portion is smaller than the cross-sectional area of ​​the wall thickness of the dilator body at a position in the intermediate region corresponding to the non-foamed resin portion, and is larger than the cross-sectional area of ​​the wall thickness of the dilator body at a position corresponding to the central portion of the tapered portion.

[0019] (7) A catheter assembly according to any one of (4) to (6), wherein the cross-sectional area of ​​the wall thickness of the dilator body at a position in the main body corresponding to the foamed resin portion is substantially the same as or smaller than the cross-sectional area at a position corresponding to the non-foamed resin portion located between the tip of the foamed resin portion and the central portion of the tapered portion.

[0020] (8) The catheter assembly according to any one of (1) to (7), wherein the dilator body has a first skin layer at least at a position corresponding to the foamed resin portion on the inner surface forming the lumen of the dilator body.

[0021] (9) The catheter assembly according to any one of (1) to (8), wherein the dilator body has a second skin layer on the outer surface at least at a position corresponding to the foamed resin portion.

[0022] The dilator included in the catheter assembly of the present invention has a distal region that protrudes distally beyond the distal end of the catheter body when the dilator body is inserted through the lumen of the catheter body (inserted state). The dilator body also has a foamed resin portion containing fine bubbles within the wall thickness of the dilator body, spanning the boundary between the base end of the distal region and the distal end of the intermediate region. By providing the foamed resin portion in the distal region, the amount of resin in the wall thickness at the location where the foamed resin portion is provided is reduced. This improves the flexibility of the dilator body at the location where the foamed resin portion is provided, improving the guidewire followability of the distal region of the dilator body. Furthermore, the fine bubbles contained in the foamed resin portion can absorb stress applied to the dilator body when it is bent, etc. This improves the flexibility of the dilator body at the location where the foamed resin portion is provided. This improves the guidewire followability of the dilator body and the catheter body in the inserted state of the catheter assembly. Furthermore, the foamed resin portion of the dilator body is positioned so as to straddle the boundary between the base end of the distal region of the dilator body and the tip of the intermediate region. Therefore, in the inserted state, the catheter assembly exhibits a gradual change in rigidity between the vicinity of the base end of the distal region of the dilator body and the intermediate region located proximal to the distal region and the portion where the tip of the catheter body covering the intermediate region is located. As a result, in the inserted state, the catheter assembly can suppress the occurrence of buckling near the boundary between the base end of the distal region of the dilator body and the tip of the intermediate region, improving the insertability of the catheter assembly into a biological lumen.

[0023] Fig. 3 is a diagram showing a catheter assembly according to an embodiment. Fig. 4 is a cross-sectional view showing a portion of the distal end side of the catheter assembly according to an embodiment. Fig. 5 is a cross-sectional view taken perpendicular to the axis of the dilator main body at the position indicated by arrows III-III in Fig. 2. Fig. 6 is a cross-sectional view taken perpendicular to the axis of the dilator main body at the position indicated by arrows IV-IV in Fig. 2. Fig. 7 is a cross-sectional view taken perpendicular to the axis of the dilator main body at the position indicated by arrows V-V in Fig. 2. Fig. 8 is a cross-sectional view showing a portion of the distal end side of a catheter assembly according to a modified example.

[0024] A catheter assembly 1 according to this embodiment will be described with reference to FIGS.

[0025] <Catheter Assembly 1> As shown in FIG. 1 , the catheter assembly 1 includes a dilator 10 and a catheter 300.

[0026] With the dilator body 100 of the dilator 10 inserted into the catheter hub 340 of the catheter 300 and the lumen 315 of the catheter body 310, the surgeon can detachably fix the dilator hub 200 to the cap member 350. In this specification, the catheter assembly 1 refers to a state in which the dilator body 100 is inserted into the catheter body 310 and a distal end region 110 of the dilator body 100 is formed on the distal end side of the catheter body 310 as shown in Figure 2, or a state before the dilator 10 and the catheter 300 are assembled (separated state) as shown in Figure 1.

[0027] <Catheter 300> As shown in Figures 1 and 2, the catheter 300 includes a catheter body 310 having an inner cavity 315 into which the dilator body 100 can be inserted, and a catheter hub 340 that is connected to the base end 313 of the catheter body 310 and can be connected to the dilator hub 200.

[0028] In this specification, the direction in which the catheter main body 310 extends is referred to as the "longitudinal direction (or axial direction)" and is indicated by arrows X1-X2. The direction indicated by arrow X1 is defined as the distal end side in the longitudinal direction, and the direction indicated by arrow X2 is defined as the proximal end side in the longitudinal direction. The longitudinal direction of the dilator 10 (the direction parallel to the extension direction of the central axis c1 of the dilator main body 100) is the direction indicated by arrows X1-X2, just like the longitudinal direction of the catheter main body 310. Note that arrows Y1-Y2 in the figures indicate a direction perpendicular to the longitudinal direction.

[0029] In this specification, the most distal position of each component of the catheter assembly 1 is referred to as the "distal end," and the certain range from the distal end toward the proximal end is referred to as the "distal portion." Similarly, the most proximal position of each component of the catheter assembly 1 is referred to as the "proximal end," and the certain range from the proximal end toward the distal end is referred to as the "proximal portion."

[0030] The catheter 300 can be used to introduce various medical devices into a biological lumen (e.g., a blood vessel) via the lumen 315 of the catheter body 310. There are no particular limitations on the specific method or procedure for using the catheter 300, but for example, the catheter 300 can be used to form an access path for delivering various medical devices (e.g., a stent for placement in the aorta, a device used in artificial valve replacement surgery to treat aortic stenosis, a device for treating pulmonary thrombosis, etc.) from a relatively large blood vessel running through the lower limb to various parts of the living body, using the blood vessel in the lower limb as the insertion target site.

[0031] The catheter assembly 1 can be used, for example, in the following procedure.

[0032] With the dilator 10 connected to the catheter 300, the surgeon inserts the catheter body 310 into a perforation formed in the living body so as to connect the outside of the living body with the biological lumen into which the catheter body 310 is to be inserted, and pushes open the perforation. The dilator 10 prevents the catheter body 310 from being bent or otherwise damaged when the catheter body 310 is inserted into the biological lumen through the perforation as described above.

[0033] Prior to inserting the catheter body 310 together with the dilator 10 into a biological lumen as described above, the surgeon passes a guide wire, which is disposed between the biological lumen and the outside of the living body, through the dilator body 100 via a perforation formed in the living body, and inserts the dilator body 100 and the catheter body 310 along the guide wire into the biological lumen. After inserting the distal end 101 of the dilator body 100 to a predetermined position in the biological lumen, the surgeon removes the dilator body 100 from the catheter body 310. By using the lumen 315 of the catheter body 310 from which the dilator body 100 has been removed as an access route, the surgeon can deliver various medical devices to desired positions in the biological lumen.

[0034] As shown in FIGS. 1 and 2, the catheter body 310 has a distal end 311 and a proximal end 313 disposed inside the catheter hub 340 .

[0035] A tip opening 311a is provided at the tip of the catheter body 310. A base opening 313a is provided at the base end of the catheter body 310.

[0036] The lumen 315 of the catheter body 310 extends continuously between the distal end opening 311a and the proximal end opening 313a. The lumen 315 of the catheter body 310 has substantially the same diameter along the longitudinal direction of the catheter body 310.

[0037] The proximal end 313 of the catheter body 310 is disposed within the catheter hub 340 so that a proximal end opening 313 a provided at the proximal end of the catheter body 310 communicates with the interior of the catheter hub 340 .

[0038] As shown in FIGS. 1 and 2, the distal end portion 311 of the catheter body 310 can be configured to have a tapered shape in which the outer diameter decreases toward the distal end.

[0039] As shown in Figures 1 and 2, the catheter body 310 has a first region 320A and a second region 320B located proximal to the first region 320A and having a reinforcing member 330 within the wall thickness 316 of the catheter body 310.

[0040] The first region 320A of the catheter body 310 does not have a reinforcing member 330.

[0041] 1 and 2 , the first region 320A is a region extending in the longitudinal direction from the distal end of the catheter main body 310 to the distal end of the most distal portion 331 of the reinforcing member 330. The second region 320B is a region extending in the longitudinal direction from the distal end of the most distal portion 331 of the reinforcing member 330 to the proximal end of the catheter main body 310.

[0042] The first region 320A of the catheter body 310 does not include the reinforcing member 330. Therefore, the first region 320A located at the distal end of the catheter body 310 has high flexibility, improving its ability to conform to a curved biological lumen when passing through a biological lumen, thereby improving the insertability of the catheter assembly 1 into a biological lumen. Furthermore, the second region 320B of the catheter body 310 located at the proximal end of the first region 320A includes the reinforcing member 330. Therefore, the catheter body 310 has appropriate rigidity in a position (second region 320B) closer to the proximal end than the first region 320A. This allows the catheter assembly 1 to efficiently transmit a pushing force applied by an operator or the like from the second region 320B side (proximal side) of the catheter body 310 toward the distal end.

[0043] The reinforcing member 330 may be disposed, for example, so as to extend in a spiral shape around the central axis of the catheter body 310. However, there are no particular limitations on the arrangement of the reinforcing member 330.

[0044] The reinforcing member 330 may be configured, for example, by a member having a rectangular cross section along the axial direction as shown in Fig. 2. However, there are no particular limitations on the cross-sectional shape of the reinforcing member 330.

[0045] The reinforcing member 330 can be made of, for example, a material harder than the resin material that makes up the wall 316 of the catheter body 310. When the wall 106 of the catheter body 310 is made of a resin material exemplified below, the reinforcing member 330 can be made of, for example, stainless steel such as SUS304, SUS316, or precipitation hardened stainless steel (PH stainless steel), or a metal material such as tungsten, aluminum, or a Ni-Ti alloy.

[0046] The wall 316 of the catheter body 310 can be made of a polymer material, such as polyolefin (e.g., polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or a mixture of two or more thereof), polyolefin elastomer, crosslinked polyolefin, polyvinyl chloride, polyamide, polyamide elastomer, polyester, polyester elastomer, polyurethane, polyurethane elastomer, fluororesin (e.g., polytetrafluoroethylene, tetrafluoroethylene-ethylene copolymer), polycarbonate, polystyrene, polyacetal, polyimide, polyetherimide, polyetheretherketone, or a mixture thereof. The wall 106 of the catheter body 310 can be configured to have multiple layers (e.g., inner and outer layers) made of the same or different resin materials. When the wall 106 of the catheter body 310 has a two-layer structure consisting of an inner layer and an outer layer, the reinforcing member 330 can be disposed between the outer surface of the inner layer and the inner surface of the outer layer. The catheter body 310 may also be configured so that the reinforcing member 330 is not disposed within the wall thickness 316 .

[0047] 1, a valve body 360 is disposed inside the catheter hub 340. The valve body 360 is configured to allow the dilator body 100 and a medical device to be inserted into a biological lumen to be inserted therethrough.

[0048] The valve body 360 prevents a gap from being formed between the valve body 360 and the dilator body 100 or a medical device when the dilator body 100 or a medical device is inserted into the valve body 360. By preventing the formation of the above-mentioned gap, the valve body 360 prevents blood or liquid such as physiological saline injected into the catheter hub 340 from flowing back toward the base end side of the cap member 350 connected to the catheter hub 340.

[0049] The catheter hub 340 has a first port portion 371 and a second port portion 372 that communicate with the interior of the catheter hub 340 .

[0050] A tube 381 connected to a three-way stopcock 390 for supplying a liquid such as physiological saline to the inside of the catheter hub 340 can be connected to the first port portion 371 .

[0051] A suction device can be connected to the second port 372 via a tube 382. The suction device can be used when performing a procedure to aspirate a blood clot or the like in a vein. Note that the installation of the second port 372 can be omitted as appropriate depending on the intended use of the catheter assembly 1, etc.

[0052] The catheter 300 has a cap member 350 connected to the proximal end of the catheter hub 340. The cap member 350 has an opening (not shown) that communicates with the inside of the catheter hub 340. The surgeon or the like can insert the dilator body 100 into the inside of the catheter hub 340 and the lumen 315 of the catheter body 310 by pushing the dilator body 100 from the proximal end side of the cap member 350.

[0053] <Dilator 10> As shown in Figures 1 and 2, the dilator 10 comprises a dilator body 100 having an inner cavity 105 penetrating between the tip and base ends, and a dilator hub 200 connected to the base end 103 of the dilator body 100 and having an opening 207 communicating with the inner cavity 105 of the dilator body 100.

[0054] As shown in FIG. 2, the dilator body 100 has a distal end opening 101 a at its distal end that communicates with the lumen 105 .

[0055] As shown in FIG. 1, the dilator body 100 has a proximal end opening 103 a in communication with the lumen 105 at its proximal end.

[0056] 2 and 3 to 5, the lumen 105 of the dilator body 100 extends from the base end side to the tip end side with a substantially constant diameter d1. Note that Figures 3 to 6 are cross-sectional views taken perpendicular to the axis of the dilator body 100 at each position indicated by arrows III-III, IV-IV, V-V, and VI-VI in Figure 2.

[0057] As shown in FIG. 1 , the proximal end 103 of the dilator body 100 is disposed in the internal space 205 of the dilator hub 200 .

[0058] The inner cavity 105 of the dilator body 100 communicates with the opening 207 of the dilator hub 200 via the internal space 205 of the dilator hub 200 .

[0059] As shown in FIGS. 1 and 2 , the dilator body 100 has a distal region 110 , a proximal region 120 , and an intermediate region 130 located between the distal region 110 and the proximal region 120 .

[0060] 2, the distal end region 110 of the dilator body 100 is a region that protrudes distally beyond the distal end of the catheter body 310 when the dilator body 100 is inserted through the lumen 315 of the catheter body 310 (hereinafter also referred to as the "inserted state"). More specifically, the distal end region 110 is a region located on the distal end side of the dilator body 100 that protrudes distally beyond the distal end of the catheter body 310 when the dilator hub 200 is fixed to or in contact with the cap member 350 in the inserted state.

[0061] As shown in FIG. 1 , the proximal region 120 is a region of the dilator body 100 that is disposed within the dilator hub 200 .

[0062] As shown in FIGS. 1 and 2, the intermediate region 130 is a region extending between the distal region 110 and the proximal region 120 .

[0063] The intermediate region 130 and the proximal region 120 are configured to have approximately the same outer diameter.

[0064] The imaginary lines A1, A2, and A3 on the cross-sectional view of the catheter assembly 1 (dilator body 100 and catheter body 310) along the axial direction shown in FIG. 2 indicate the following positions.

[0065] The position marked with the imaginary line A1 is the tip of the dilator body 100 (same position as the tip 117a of the tapered portion 117 of the dilator body 100 and the tip of the tip region 110 of the dilator body 100).

[0066] The position marked with the imaginary line A2 is the boundary between the base end of the tip region 110 of the dilator body 100 and the tip of the intermediate region 130 of the dilator body 100.

[0067] The position marked with the imaginary line A3 is the boundary between the tip of the main body portion 115 of the dilator body 100 and the base end 117b of the tapered portion 117 of the dilator body 100.

[0068] As shown in FIG. 2 , the dilator body 100 has a foamed resin portion 140 containing a group of fine bubbles 145 inside the wall thickness 106 of the dilator body 100, spanning the boundary between the base end of the tip region 110 and the tip of the intermediate region 130.

[0069] The above phrase "straddling the boundary between the base end of the tip region 110 and the tip of the intermediate region 130" means that the foamed resin portion 140 containing the group of fine bubbles 145 exists over a predetermined range in the longitudinal direction, straddling the boundary between the base end of the tip region 110 and the tip of the intermediate region 130.

[0070] The microbubble groups 145 are voids (spaces) within the wall 106 of the dilator body 100 that are not filled with the resin material that constitutes the wall 106. Therefore, the portion (area) of the dilator body 100 where the foamed resin section 140 is provided has a smaller amount of resin material per unit area (the amount of resin material when compared in a cross section perpendicular to the axis at the same position in the longitudinal direction) than when the dilator body 100 does not have the foamed resin section 140.

[0071] By including the foamed resin portion 140, the dilator body 100 reduces the amount of resin in the wall thickness 106 at the position where the foamed resin portion 140 is provided in the tip region 110 of the dilator body 100. As a result, the flexibility of the dilator body 100 is improved at the position where the foamed resin portion 140 is provided, improving the followability of the tip region 110 of the dilator body 100 to the guidewire and reducing the insertion load of the tip region 110.

[0072] Furthermore, the microbubble groups 145 can absorb stress applied to the dilator body 100 when the dilator body 100 is bent, etc. Therefore, the flexibility of the dilator body 100 at the position where the foamed resin section 140 is provided is improved when the dilator body 100 is bent, etc. This improves the followability of the dilator body 100 and the catheter body 310 to the guidewire when the catheter assembly 1 is inserted.

[0073] As described above, the foamed resin portion 140 is disposed so as to straddle the boundary between the base end of the tip region 110 of the dilator body 100 and the tip of the intermediate region 130. Therefore, in the inserted state, the catheter assembly 1 exhibits a gradual change in rigidity between the vicinity of the base end of the tip region 110 of the dilator body 100 and the intermediate region 130 located on the base end side of the tip region 110 and the portion where the tip portion 311 of the catheter body 310 covering the intermediate region 130 is located. As a result, in the inserted state, the catheter assembly 1 can suppress the occurrence of buckling near the boundary between the base end of the tip region 110 of the dilator body 100 and the tip of the intermediate region 130, thereby improving the insertability of the catheter assembly 1 into a biological lumen.

[0074] The resin material constituting the wall 106 of the dilator body 100 may be, for example, a resin material such as high-density polyethylene, low-density polyethylene, vinyl chloride, polyurethane, polyamide, or polyester; an elastomer material such as polyurethane elastomer, polyamide elastomer, or polyester elastomer; or a combination of two or more of these materials (such as a polymer blend). The wall 106 of the portion where the non-foamed resin portions 150A and 150B (described below) are located may be made of the same resin material as the above-mentioned examples.

[0075] A contrast agent that is opaque to radiography can be contained inside the wall 106 of the dilator body 100. Specifically, the wall 106 of the dilator body 100 can be made of a material obtained by kneading the resin material exemplified above with a contrast agent. As the contrast agent, for example, powdered gold, titanium, bismuth, tungsten, or the like can be used.

[0076] Each of the fine bubbles in the fine bubble group 145 can be composed of, for example, air-filled bubbles.

[0077] Each microbubble in the microbubble group 145 can be configured to have a substantially elliptical shape with a major axis aligned along the longitudinal direction and a minor axis aligned along a direction perpendicular to the longitudinal direction, in a cross section along the longitudinal direction shown in Fig. 2. When each microbubble is configured as an ellipse as described above, the size of each microbubble can be, for example, 50 µm in the major axis direction and 20 µm in the minor axis direction, in a cross section along the longitudinal direction shown in Fig. 2.

[0078] The shape (the longitudinal cross-sectional shape shown in FIG. 2 and the cross-sectional shape perpendicular to the axis shown in FIG. 3 ) and size of each micro-bubble of the micro-bubble group 145 are not particularly limited. There are also no particular limitations on the number of micro-bubbles contained in the foamed resin portion 140.

[0079] As shown in FIG. 2, the tip region 110 has a main body portion 115 having an outer diameter D2 (see FIG. 3) that is approximately the same as the outer diameter D1 (see FIG. 6) of the intermediate region 130, and a tapered portion 117 that extends from the tip of the main body portion 115 toward the tip side and whose outer diameter decreases from the base end side toward the tip side.

[0080] As shown in Figure 2, the foamed resin portion 140 is located so as to straddle the boundary between the tip of the main body portion 115 and the base end 117b of the tapered portion 117, and the tip 141 of the foamed resin portion 140 is located further towards the tip side than the base end 117b of the tapered portion 117.

[0081] The above phrase "straddling the boundary between the tip of the main body portion 115 and the base end 117b of the tapered portion 117" means that the foamed resin portion 140 containing the fine bubbles 145 extends over a predetermined range in the longitudinal direction, straddling the boundary between the tip of the main body portion 115 and the base end 117b of the tapered portion 117.

[0082] The dilator body 100 is provided with a tapered portion 117, so that the outer diameter of the distal end region 110 gradually decreases from the base end 117b of the tapered portion 117 to the tip 117a. This improves the insertability of the distal end region 110 of the dilator body 100 into a biological lumen. Furthermore, the diameter d1 of the lumen 105 of the dilator body 100 is approximately constant along the axial direction. Therefore, the wall thickness 106 of the distal end region 110 of the dilator body 100 gradually decreases from the base end 117b of the tapered portion 117 to the tip 117a. This improves the flexibility of the dilator body 100 near the tip end 101 of the distal end region 110.

[0083] The main body 115, which is located closer to the base end than the tapered portion 117, is not configured such that its outer diameter decreases toward the tip end, as is the case with the tapered portion 117, but has a substantially constant outer diameter D2 along the axial direction. Furthermore, as described above, the diameter d1 of the lumen 105 of the dilator body 100 is substantially constant along the axial direction. Therefore, the main body 115 has a substantially constant wall thickness 106 along the axial direction. As a result, the wall thickness 106 of the main body 115 is greater than the wall thickness 106 of the portion located on the tip 117a side of the tapered portion 117. This may result in the dilator body 100 being configured such that the difference in rigidity at the boundary between the base end 117b of the tapered portion 117 and the tip of the main body 115 is excessively large. If the dilator body 100 is configured with an excessively large difference in rigidity between the base end 117b of the tapered portion 117 and the tip of the main body portion 115, buckling may occur near the boundary between the base end 117b of the tapered portion 117 and the tip of the main body portion 115, which may result in a decrease in the insertability of the tip region 110, where the tapered portion 117 and the main body portion 115 are located, into the biological lumen.

[0084] In consideration of the above-mentioned problems, in the present embodiment, the dilator body 100 has a foamed resin portion 140 arranged from a position distal to the base end 117b of the tapered portion 117 to the main body 115, which is positioned proximal to the base end 117b of the tapered portion 117. By arranging the foamed resin portion 140 in this manner, the dilator body 100 has a gentle difference in rigidity at the boundary between the base end 117b of the tapered portion 117 and the tip of the main body 115. Therefore, the dilator body 100 can prevent buckling near the boundary between the base end 117b of the tapered portion 117 and the tip of the main body 115, which is caused by the difference in rigidity at the boundary between the base end 117b of the tapered portion 117 and the tip of the main body 115.

[0085] The distal region 110 also has a main body 115 located proximally of the proximal end 117b of the tapered portion 117. In the inserted state, the main body 115 protrudes from the lumen 315 of the catheter 300 (see FIG. 2). As described above, the proximal end 143 of the foamed resin portion 140 is located proximally of the proximal end of the distal region 110. Therefore, the foamed resin portion 140 is disposed over the entire length of the main body 115 along the longitudinal direction.

[0086] As described above, the main body 115 has a greater wall thickness 106 than the region located on the distal end 117a side of the tapered portion 117. However, in the dilator body 100, the foamed resin portion 140 is provided from the distal end of the main body 115 to a predetermined region located on the proximal end side of the main body 115 (a predetermined region extending from the distal end of the intermediate region 130 toward the proximal end), and the foamed resin portion 140 is disposed along the entire longitudinal length of the main body 115. This reduces the amount of resin material in the wall thickness 106 of the main body 115. As a result, the dilator body 100 has improved flexibility and pliability in the distal region 110 where the main body 115 is located. This effectively improves the followability of the distal region 110 of the dilator body 100 to the guidewire.

[0087] The dilator body 100 may further have, for example, another tapered section (multi-stage tapered structure) within the tapered section 117, in which the outer diameter tapers toward the tip. As shown in Figure 2, the dilator body 100 according to this embodiment is provided with an additional tapered section within the tapered section 117, which tapers from a position proximal to the tip 117a of the tapered section 117 toward the tip 117a of the tapered section 117. By having an additional tapered section within the tapered section 117 as described above, the dilator body 100 further improves the insertability of the dilator body 100 into a biological lumen.

[0088] Furthermore, even when an additional tapered section is provided within the tapered section 117 of the tip region 110, the respective sections used as references for the position at which the foamed resin section 140 is provided can be set to the tip 117a, base end 117b, and central section 117c of the tapered section 117.

[0089] 1 and 2, the dilator body 100 further has non-foamed resin portions 150A, 150B that do not contain microbubbles 145 inside the wall thickness 106 of the dilator body 100. Hereinafter, the non-foamed resin portion 150A will be referred to as the "first non-foamed resin portion 150A," and the non-foamed resin portion 150B will be referred to as the "second non-foamed resin portion 150B."

[0090] The first non-foamed resin portion 150A is located in the region between the tip of the tip region 110 (same position as the tip of the catheter body 310) and the tip 141 of the foamed resin portion 140 in the longitudinal direction of the dilator body 100.

[0091] Even when the dilator body 100 contains a contrast agent within the wall 106, the contrast agent is not contained in the voids (microbubbles 145) that are not filled with the resin material of the wall 106. Therefore, when the dilator body 100 contains a contrast agent within the wall 106, the amount of contrast agent contained within the area of ​​the foamed resin portion 140 in the orthogonal cross section is smaller than that in a portion of the dilator body 100 where the outer diameter of the foamed resin portion 140 is the same as that of the portion of the dilator body 100 where the foamed resin portion 140 is located and where the foamed resin portion 140 is not present. Therefore, the dilator body 100 has lower contrast properties in the portion of the dilator body 100 where the foamed resin portion 140 is located compared to that in a portion of the dilator body 100 where the foamed resin portion 140 is not present. To address this issue, the dilator body 100 includes a first non-foamed resin portion 150A located in the region between the tip of the distal end region 110 and the tip 141 of the foamed resin portion 140, thereby ensuring a predetermined level of contrast properties near the tip of the distal end region 110.

[0092] In particular, in this embodiment, the dilator body 100 has a tapered portion 117 whose outer diameter decreases toward the tip of the tip region 110, and therefore the wall thickness 106 and the amount of contrast agent contained therein decrease as the position approaches the tip of the tip region 110. As a result, the cross-sectional area near the tip of the tip region 110 is smaller than that of the main body portion 115 in which the foamed resin portion 140 is located, and therefore the tip region 110 is formed to have lower contrast properties than the main body portion 115. As described above, the dilator body 100 has the first non-foamed resin portion 150A located in the area between the tip of the tip region 110 and the tip 141 of the foamed resin portion 140, and therefore it is possible to prevent a significant decrease in contrast properties near the tip of the tip region 110 (near the tip 117a of the tapered portion 117).

[0093] The second non-foamed resin portion 150B is located in the region between the base end 143 of the foamed resin portion 140 and the base end of the dilator body 100 (the same position as the base end of the base end region 120).

[0094] The dilator body 100 does not have a foamed resin portion 140 containing fine bubbles 145 in the region between the base end 143 of the foamed resin portion 140 and the base end of the dilator body 100. Therefore, the wall thickness 106 of the dilator body 100 is greater in the region between the base end 143 of the foamed resin portion 140 and the base end of the dilator body 100 compared to the portion where the foamed resin portion 140 is located. Therefore, the dilator body 100 can increase the rigidity of the region between the base end 143 of the foamed resin portion 140 and the base end of the dilator body 100 compared to the portion where the foamed resin portion 140 is located. Here, the dilator body 100 has appropriate rigidity in a region toward the base end in the longitudinal direction of the dilator body 100 (for example, a region from a position closer to the base end than the longitudinal tip of the intermediate region 130 to the vicinity of the base end of the base end region 120). This allows a pushing force to be firmly transmitted from the proximal side (proximal end) of the catheter assembly 1 toward the distal end when the catheter assembly 1 is inserted into a biological lumen. This allows the surgeon or the like to smoothly insert the catheter assembly 1 into a biological lumen. As described above, the dilator body 100 has the second non-foamed resin portion 150B located in the region between the proximal end 143 of the foamed resin portion 140 and the proximal end of the dilator body 100. Therefore, when the surgeon or the like inserts the catheter assembly 1 into a biological lumen, a pushing force can be firmly transmitted from the proximal side to the distal end of the catheter assembly 1.

[0095] As shown in FIG. 2, the tip 141 of the foamed resin portion 140 is located closer to the base end than the central portion 117 c of the tapered portion 117 .

[0096] The "central portion 117c of the tapered portion 117" is the central position in the longitudinal direction of the tapered portion 117 (approximately the central position of the linear distance along the central axis c1 from the tip end 117a to the base end 117b).

[0097] The tapered portion 117, located in the distal region 110 of the dilator body 100, has an outer diameter that decreases toward the distal end. Furthermore, as described above, the diameter d1 of the lumen 105 of the dilator body 100 is substantially constant along the axial direction. Therefore, the wall thickness 106 of the tapered portion 117 decreases toward the distal end. In particular, in the region distal to the central portion 117c of the tapered portion 117, the rate of decrease in the wall thickness 106 is greater than in the main body 115. Therefore, if the dilator body 100 includes a foamed resin portion 140 containing fine bubbles 145 in the region distal to the central portion 117c of the tapered portion 117, the flexibility of the distal end portion 101 of the dilator body 100 will be excessively large. Therefore, if the dilator body 100 has a foamed resin portion 140 containing microbubbles 145 in a region distal to the central portion 117c of the tapered portion 117, buckling may occur in the region distal to the central portion 117c of the tapered portion 117 during insertion into a biological lumen, potentially reducing insertability into the biological lumen. To address this issue, the dilator body 100 has the tip 141 of the foamed resin portion 140 positioned closer to the base end than the central portion 117c of the tapered portion 117, thereby preventing the flexibility of the dilator body 100 from becoming excessively high in the region distal to the central portion 117c of the tapered portion 117. As a result, the dilator body 100 can prevent a reduction in insertability of the dilator body 100 into a biological lumen.

[0098] In the distal region 110 of the dilator body 100, the main body portion 115, which is located on the proximal side of the tapered portion 117, has the largest outer diameter. Therefore, the outer diameter of the dilator body 100 increases as it moves toward the proximal side from the central portion 117c of the tapered portion 117 (as it moves from the central portion 117c of the tapered portion 117 toward the main body portion 115). Also, as described above, the diameter d1 of the lumen 105 of the dilator body 100 is approximately constant in the axial direction. Therefore, the tapered portion 117 has an increased wall thickness 106 as it moves toward the main body portion 115, which is located on the proximal side of the tapered portion 117. In particular, the rate of decrease in the wall thickness 106 is smaller in the region proximal to the central portion 117c of the tapered portion 117 than in the region distal to the central portion 117c of the tapered portion 117. For this reason, the dilator body 100 is preferably configured to increase the flexibility of the region from the base end side of the central portion 117c of the tapered portion 117 to the main body portion 115. In this regard, as described above, in the dilator body 100, the foamed resin portion 140 is positioned so as to straddle the boundary between the tip of the main body portion 115 and the base end 117b of the tapered portion 117, and the tip 141 of the foamed resin portion 140 is positioned more distal than the base end of the tapered portion 117. Therefore, the dilator body 100 has a structure in which the flexibility near the base end 117b of the tapered portion 117 (near the tip of the main body portion 115) is suitably increased.

[0099] As shown in FIG. 2, the base end 143 of the foam resin portion 140 is located in the second region 320B of the catheter body 310 in the inserted state.

[0100] The catheter 300 does not have a reinforcing member 330 arranged in the first region 320A, but has a reinforcing member 330 arranged in the second region 320B located closer to the proximal end than the first region 320A. Therefore, in the inserted state, the catheter assembly 1 has greater rigidity at the position where the second region 320B of the catheter body 310 and the dilator body 100 overlap in the longitudinal direction than at the position where the first region 320A of the catheter body 310 and the dilator body 100 overlap in the longitudinal direction. In the catheter assembly 1, as described above, the foam resin portion 140 provided on the dilator body 100 is arranged so as to straddle the boundary between the tip region 110 and the intermediate region 130. In this configuration, if the proximal end 143 of the foamed resin portion 140 were positioned only at the position corresponding to the first region 320A (if the foamed resin portion 140 did not extend to the position corresponding to the second region 320B), the catheter assembly 1 would have a greater difference in rigidity between the portion corresponding to the first region 320A and the portion corresponding to the second region 320B in the inserted state. Therefore, when the catheter assembly 1 is inserted into a biological lumen in the inserted state, it would deform significantly near the boundary between the portion corresponding to the first region 320A and the portion corresponding to the second region 320B, which would likely cause contact between the inner surface of the dilator body 100 and the guidewire inserted into the lumen 105 of the dilator body 100, or between the outer surface of the catheter body 310 and the wall of the biological lumen. Therefore, when the catheter assembly 1 is inserted in the inserted state, insertion resistance increases as it moves through the biological lumen, reducing insertability into the biological lumen. In this embodiment, the base end 143 of the foamed resin section 140 is located in the second region 320B of the catheter body 310 in the inserted state. This prevents the difference in rigidity between the portion corresponding to the first region 320A and the portion corresponding to the second region 320B from becoming excessively large in the catheter assembly 1. Therefore, when the catheter assembly 1 is inserted into a biological lumen in the inserted state, it is possible to suppress sudden deformation near the boundary between the portion corresponding to the first region 320A and the portion corresponding to the second region 320B, improving insertability into a biological lumen.

[0101] The cross-sectional area of ​​the wall thickness 106 of the dilator body 100 at a position corresponding to the foamed resin portion 140 in the main body portion 115 is smaller than the cross-sectional area of ​​the wall thickness 106 of the dilator body 100 at a position corresponding to the second non-foamed resin portion 150B of the intermediate region 130, and is larger than the cross-sectional area of ​​the wall thickness 106 of the dilator body 100 at a position corresponding to the central portion 117c of the tapered portion 117.

[0102] The relationship in size between the cross-sectional areas of the wall thickness 106 can be defined based on the area of ​​the wall thickness 106 shown in Figures 3, 6, and 4 (the area excluding the area of ​​the portion occupied by the lumen 105 and the microbubble group 145 on the orthogonal cross section of the main body portion 115). Figure 3 shows an orthogonal cross section of the dilator body 100 at a position corresponding to the foamed resin portion 140 in the main body portion 115. Figure 6 shows an orthogonal cross section of the dilator body 100 at a position corresponding to the second non-foamed resin portion 150B of the intermediate region 130. Figure 4 shows an orthogonal cross section of the central portion 117c of the tapered portion 117.

[0103] The cross-sectional area of ​​the wall thickness 106 of the dilator body 100 at a position in the main body 115 corresponding to the foamed resin portion 140 is smaller than the cross-sectional area of ​​the wall thickness 106 of the dilator body 100 at a position in the intermediate region 130 corresponding to the second non-foamed resin portion 150B. Therefore, the dilator body 100 is configured so that the flexibility of the portion of the main body 115 where the foamed resin portion 140 is provided is greater than the flexibility of the portion of the intermediate region 130 where the second non-foamed resin portion 150B is provided.

[0104] Furthermore, the cross-sectional area of ​​the wall thickness 106 of the dilator body 100 at a position in the main body 115 corresponding to the foamed resin portion 140 is larger than the cross-sectional area of ​​the wall thickness 106 of the dilator body 100 at a position corresponding to the central portion 117c of the tapered portion 117. Therefore, the dilator body 100 is configured so that the flexibility of the portion of the main body 115 where the foamed resin portion 140 is provided is smaller than the flexibility of the central portion 117c of the tapered portion 117 and the region distal to the central portion 117c of the tapered portion 117.

[0105] The relationship in magnitude of the flexibility described above can be summarized as follows: "flexibility of central portion 117c of tapered portion 117 and the region distal to central portion 117c of tapered portion 117 > flexibility of the portion of main body 115 where foamed resin portion 140 is provided > flexibility of the portion of intermediate region 130 where second non-foamed resin portion 150B is provided." In addition, as described above, tip 141 of foamed resin portion 140 is located closer to the base end than central portion 117c of tapered portion 117.

[0106] By providing the above-described relationship between the magnitudes of flexibility, the dilator body 100 is configured so that the flexibility of the portion of the main body 115 where the foamed resin portion 140 is provided is less than the flexibility of the central portion 117c of the tapered portion 117 and the region distal to the central portion 117c of the tapered portion 117. In other words, the portion of the main body 115 where the foamed resin portion 140 is provided has higher rigidity than the central portion 117c of the tapered portion 117 and the region distal to the central portion 117c of the tapered portion 117. Therefore, when the distal region 110 of the dilator body 100 is inserted into a biological lumen, the portion of the main body 115 where the foamed resin portion 140 is provided is deformed, and an increase in the insertion resistance of the dilator body 100 can be suppressed. Furthermore, because the central portion 117c of the tapered portion 117 and the region distal to the central portion 117c of the tapered portion 117 do not have the foamed resin portion 140, it is possible to prevent the flexibility of the central portion 117c of the tapered portion 117 and the region distal to the central portion 117c of the tapered portion 117 from becoming excessively high. Therefore, when the distal region 110 of the dilator body 100 is inserted into a biological lumen, it is possible to prevent deformation such as buckling from occurring in the central portion 117c of the tapered portion 117 and the region distal to the central portion 117c of the tapered portion 117. In addition, by providing the above-described relationship in flexibility, the dilator body 100 is configured so that the flexibility of the portion of the main body 115 where the foamed resin portion 140 is provided is greater than the flexibility of the portion of the intermediate region 130 where the second non-foamed resin portion 150B is provided. That is, in the dilator body 100, the portion of the main body 115 where the foamed resin portion 140 is provided and the portion of the intermediate region 130 where the foamed resin portion 140 is provided are configured to be more flexible than the portion of the intermediate region 130 where the second non-foamed resin portion 150B is provided. Therefore, in the inserted state of the catheter assembly 1, the difference in rigidity from the portion of the main body 115 where the foamed resin portion 140 is provided to the portion of the intermediate region 130 where the second non-foamed resin portion 150B is provided is alleviated. For these reasons, the catheter assembly 1 has improved insertability into a biological lumen in the inserted state.

[0107] The cross-sectional area of ​​the thickness 106 of the dilator body 100 at a position in the main body 115 corresponding to the foamed resin portion 140 is approximately the same as the cross-sectional area of ​​a position (region) 118 corresponding to the first non-foamed resin portion 150A located between the tip 141 of the foamed resin portion 140 and the central portion 117c of the tapered portion 117, or is smaller than the cross-sectional area of ​​the position 118 (region) corresponding to the first non-foamed resin portion 150A located between the tip 141 of the foamed resin portion 140 and the central portion 117c of the tapered portion 117.

[0108] The relationship in size between the cross-sectional areas of the wall thickness 106 can be defined based on the area of ​​the wall thickness 106 shown in Figures 3 and 5 (the area excluding the area of ​​the portion occupied by the lumen 105 and the microbubble group 145 on the cross-sectional view of the main body 115 perpendicular to the axis). Figure 5 shows a cross-sectional view of the first non-foamed resin portion 150A located between the tip 141 of the foamed resin portion 140 and the central portion 117c of the tapered portion 117.

[0109] When the cross-sectional area of ​​the wall thickness 106 of the dilator body 100 at a position in the main body 115 corresponding to the foamed resin portion 140 is configured to be approximately the same as the cross-sectional area of ​​a position 118 corresponding to the first non-foamed resin portion 150A located between the tip 141 of the foamed resin portion 140 and the central portion 117c of the tapered portion 117, the flexibility of the portion of the main body 115 where the foamed resin portion 140 is provided will be approximately the same as the flexibility of the above-mentioned position 118.

[0110] Furthermore, when the cross-sectional area of ​​the wall thickness 106 of the dilator body 100 at a position in the main body 115 corresponding to the foamed resin portion 140 is configured to be smaller than the cross-sectional area of ​​a position 118 corresponding to the first non-foamed resin portion 150A located between the tip 141 of the foamed resin portion 140 and the central portion 117c of the tapered portion 117, the flexibility of the portion of the main body 115 where the foamed resin portion 140 is provided becomes greater than the flexibility of the above-mentioned position 118.

[0111] The distal end region 110 has an outer diameter that increases from the distal end 117a to the proximal end 117b of the tapered portion 117, and accordingly, the wall thickness 106 gradually increases. In particular, in the portion closer to the proximal end than the central portion 117c of the tapered portion 117, the rate of increase in the wall thickness 106 increases toward the main body portion 115, and flexibility decreases. Therefore, as described above, in this embodiment, the distal end 141 of the foamed resin portion 140 is disposed so as to straddle the boundary between the distal end of the main body portion 115 and the proximal end 117b of the tapered portion 117. Furthermore, the distal end 141 of the foamed resin portion 140 is located closer to the proximal end than the central portion 117c of the tapered portion 117. When such a configuration is adopted, position 118, which corresponds to first non-foamed resin portion 150A located between center portion 117c of tapered portion 117 and tip 141 of foamed resin portion 140, is located at the base end of first non-foamed resin portion 150A adjacent to tip 141 of foamed resin portion 140. Furthermore, position 118 is an area near the boundary between foamed resin portion 140 and first non-foamed resin portion 150A, and therefore is a portion to which a load is applied when tip region 110 of dilator body 100 is inserted into a biological lumen. Therefore, if the position (region) corresponding to the first non-foamed resin portion 150A located between the central portion 117c of the tapered portion 117 and the tip 141 of the foamed resin portion 140 is configured to be more flexible (more flexible) than the portion of the main body portion 115 where the foamed resin portion 140 is provided (the tip of the main body portion 115), the load applied when inserting the tip region 110 of the dilator main body 100 into the biological lumen may cause deformation of the above-mentioned position 118, reducing the insertability of the dilator main body 100 into the biological lumen. In the present embodiment, the flexibility of the position 118 is configured to be substantially the same as or less than the flexibility of the portion of the main body 115 where the foamed resin section 140 is provided. This reduces the load that occurs at the position corresponding to the first non-foamed resin section 150A located between the center 117c of the tapered section 117 and the tip 141 of the foamed resin section 140 (the region near the boundary between the foamed resin section 140 and the first non-foamed resin section 150A) when the dilator body 100 is inserted into a biological lumen, thereby reducing deformation at the position 118. This improves the insertability of the dilator body 100 into a biological lumen.

[0112] Furthermore, the flexibility of a position 118 corresponding to the first non-foaming resin portion 150A located between the tip 141 of the foaming resin portion 140 and the central portion 117c of the tapered portion 117 is smaller than the flexibility of a region located distally of the central portion 117c of the tapered portion 117. This prevents the flexibility of the position 118 from being excessively large. This prevents the dilator body 100 from being excessively bent at the position 118, causing buckling or the like, when the dilator body 100 is inserted into a biological lumen. Furthermore, it is preferable that the flexibility of the position 118 corresponding to the first non-foaming resin portion 150A located between the tip 141 of the foaming resin portion 140 and the central portion 117c of the tapered portion 117 be configured to be substantially the same as the flexibility of the portion of the main body 115 where the foaming resin portion 140 is provided. This configuration prevents the flexibility of the position 118 from being excessively small compared to the flexibility of the portion of the main body 115 where the foamed resin portion 140 is provided. Therefore, the dilator body 100 can prevent an excessive difference in rigidity from occurring in the region from the center portion 117c of the tapered portion 117 to the portion of the main body 115 where the foamed resin portion 140 is provided. Therefore, the dilator body 100 can more effectively prevent buckling or the like caused by excessive bending at the position 118 when the dilator body 100 is inserted into a biological lumen.

[0113] As shown in FIGS. 2 and 3 , the dilator body 100 has a first skin layer 107 at a position corresponding to at least the foamed resin portion 140 on the inner surface 100 a that forms the lumen 105 of the dilator body 100 .

[0114] The first skin layer 107 prevents the fine bubbles 145 contained in the foamed resin portion 140 from forming in a manner that is continuous with the inner surface 100a. Therefore, the dilator body 100 can prevent the fine bubbles 145 from being exposed on the inner surface 100a at the position where the foamed resin portion 140 is provided, thereby preventing unevenness from being formed on the inner surface 100a. By providing the first skin layer 107, the dilator body 100 has a smooth inner surface 100a. This prevents the guidewire inserted into the lumen 105 of the dilator body 100 from getting caught on such unevenness, which could impair the insertability of the guidewire.

[0115] In this embodiment, the first skin layer 107 is formed as part of the wall thickness 106 of the dilator body 100. In other words, the first skin layer 107 is formed as part of the wall thickness 106 that covers the fine bubbles 145 contained in the foamed resin portion 140 on the inner surface 100a side. However, the first skin layer 107 can also be formed from a material other than the material that constitutes the wall thickness 106 of the dilator body 100. In such a configuration, the first skin layer 107 can be formed from a film-like member or the like that is arranged to cover the fine bubbles 145 from the inner surface 100a side. For example, the first skin layer 107 may be a low-friction resin layer such as PTFE (polytetrafluoroethylene) that is arranged to cover the fine bubbles 145 from the inner surface 100a side of the dilator body 100.

[0116] As shown in FIGS. 2 and 3, the dilator body 100 has a second skin layer 108 at least at a position on the outer surface 100b corresponding to the foamed resin portion 140.

[0117] The second skin layer 108 prevents the fine bubbles 145 contained in the foamed resin portion 140 from forming a contiguous region with the outer surface 100b. This prevents the fine bubbles 145 from being exposed on the outer surface 100b at the location where the foamed resin portion 140 is provided, thereby preventing the formation of irregularities on the outer surface 100b. By providing the second skin layer 108, the dilator body 100 has a smooth outer surface 100b. This prevents the dilator body 100, in the inserted state, from forming a clearance between the outer surface 100b of the dilator body 100 and the inner surface of the catheter body 310, and from applying stress to the inner wall of the biological lumen (e.g., a blood vessel wall) due to the irregularities.

[0118] In this embodiment, the second skin layer 108, like the first skin layer 107, is formed from a portion of the wall thickness 106 of the dilator body 100. In other words, the second skin layer 108 is formed from a portion of the wall thickness 106 that covers the fine bubbles 145 contained in the foamed resin portion 140 on the outer surface 100b side. However, the second skin layer 108 can also be formed from a material other than the material that forms the wall thickness 106 of the dilator body 100. In such a configuration, the second skin layer 108 can be formed from, for example, a film-like member that is arranged so as to cover the fine bubbles 145 from the outer surface 100b side.

[0119] Below, examples of suitable dimensions of each part of the catheter assembly 1 (dilator body 100 and catheter body 310) will be described.

[0120] The longitudinal length of the dilator body 100 (the axial length from the tip to the base end) can be configured to be, for example, 300 mm to 1000 mm.

[0121] When the longitudinal length of the dilator body 100 is configured with the above dimensions, the longitudinal length of the tip region 110 of the dilator body 100 can be configured, for example, to be 30 mm to 150 mm, the longitudinal length of the intermediate region 130 of the dilator body 100 can be configured, for example, to be 130 mm to 965 mm, and the longitudinal length of the base end region 120 of the dilator body 100 can be configured, for example, to be 5 mm to 20 mm.

[0122] Furthermore, when the longitudinal length of the tip region 110 of the dilator body 100 is configured to the above dimensions, the longitudinal length of the tapered portion 117 can be configured to be, for example, 20 mm to 100 mm, and the longitudinal length of the main body portion 115 can be configured to be, for example, 10 mm to 50 mm.

[0123] Furthermore, when the longitudinal length of the tapered portion 117 and the longitudinal length of the main body portion 115 are configured as described above, the position of the tip 141 of the foamed resin portion 140 can be positioned 15 mm to 75 mm toward the tip from the position of the base end of the tip region 110 (the position shown by the virtual line A2 in Figure 2), and the position of the base end 143 of the foamed resin portion 140 can be positioned 10 mm to 45 mm toward the base from the position of the base end of the tip region 110 (the position shown by the virtual line A2 in Figure 2).

[0124] The outer diameter D2 of the main body 115 of the dilator body 100 (the same size as the outer diameter D1 of the intermediate region 130) can be, for example, 5.0 mm to 10.0 mm. The diameter d1 of the lumen 105 of the dilator body 100 can be, for example, 0.9 mm to 2.0 mm.

[0125] The thickness of the first skin layer 107 of the dilator body 100 (thickness on the cross section perpendicular to the axis in FIG. 3) can be, for example, 0.1 mm to 1.0 mm. The thickness of the second skin layer 108 of the dilator body 100 (thickness on the cross section perpendicular to the axis in FIG. 3) can be, for example, 0.1 mm to 1.0 mm.

[0126] The longitudinal length of the catheter body 310 (the axial length from the distal end to the proximal end) can be configured to be, for example, 250 mm to 950 mm.

[0127] When the longitudinal length of the catheter body 310 is configured to the above dimensions, the longitudinal length of the first region 320A of the catheter body 310 can be configured to be, for example, 5 mm to 20 mm, and the longitudinal length of the second region 320B of the catheter body 310 can be configured to be, for example, 230 mm to 945 mm.

[0128] Furthermore, when the longitudinal lengths of the regions 320A, 320B of the catheter body 310 are configured to the above dimensions, in the inserted state, the length by which the foamed resin portion 140 of the dilator body 100 overlaps with the first region 320A in the longitudinal direction can be configured to be, for example, 5 mm to 20 mm, and the length by which the foamed resin portion 140 of the dilator body 100 overlaps with the second region 320B in the longitudinal direction can be configured to be, for example, 5 mm to 40 mm.

[0129] The outer diameter of the catheter body 310 (the outer diameter of the second region 320B in this embodiment) can be set to, for example, 5.5 mm to 10.5 mm. The diameter of the lumen 315 of the catheter body 310 can be set to, for example, 5 mm to 10 mm.

[0130] As described above, the catheter assembly 1 according to this embodiment includes a dilator 10 including the dilator body 100 having the lumen 105 penetrating between the tip and base ends, and a dilator hub 200 connected to the base end 103 of the dilator body 100 and having an opening 207 communicating with the lumen 105 of the dilator body 100, and a catheter 300 including the catheter body 310 having the lumen 315 into which the dilator body 100 can be inserted, and a catheter hub 340 connected to the base end 313 of the catheter body 310 and connectable to the dilator hub 200. The dilator body 100 has a distal region 110, a proximal region 120, and an intermediate region 130 located between the distal region 110 and the proximal region 120. The distal region 110 of the dilator body 100 is configured as a region that protrudes distally beyond the distal end of the catheter body 310 when the dilator body 100 is inserted through the lumen 315 of the catheter body 310 (inserted state). The dilator body 100 has a foamed resin portion 140 containing a group of fine bubbles 145 inside the wall thickness 106 of the dilator body 100, spanning the boundary between the proximal end of the distal region 110 and the distal end of the intermediate region 130.

[0131] As described above, the dilator body 100 included in the dilator 10 has a distal region 110 that protrudes distally beyond the distal end 311 of the catheter body 310 in the inserted state. The dilator body 100 also has a foamed resin portion 140 containing fine bubbles 145 within the wall thickness 106 of the dilator body 100, spanning the boundary between the base end of the distal region 110 and the distal end of the intermediate region 130. By having the foamed resin portion 140 provided in the distal region 110, the amount of resin in the wall thickness 106 at the location where the foamed resin portion 140 is provided is reduced. This improves the flexibility of the dilator body 100 at the location where the foamed resin portion 140 is provided, improving the followability of the distal region 110 of the dilator body 100 to the guidewire.

[0132] Furthermore, the microbubbles 145 contained in the foamed resin portion 140 can absorb stress applied to the dilator body 100 when the dilator body 100 is bent, etc. This improves the flexibility of the dilator body 100 at the location where the foamed resin portion 140 is provided. This improves the followability of the dilator body 100 and the catheter body 310 to the guidewire when the catheter assembly 1 is inserted.

[0133] Furthermore, the foamed resin portion 140 of the dilator body 100 is disposed so as to straddle the boundary between the base end of the tip region 110 of the dilator body 100 and the tip of the intermediate region 130. Therefore, in the inserted state, the catheter assembly 1 exhibits a gradual change in rigidity between the vicinity of the base end of the tip region 110 of the dilator body 100 and the intermediate region 130 located on the proximal side of the tip region 110 and the portion where the tip portion 311 of the catheter body 310 covering the intermediate region 130 is located. As a result, in the inserted state, the catheter assembly 1 can suppress the occurrence of buckling near the boundary between the base end of the tip region 110 of the dilator body 100 and the tip of the intermediate region 130, thereby improving the insertability of the catheter assembly 1 into a biological lumen.

[0134] In addition, the tip region 110 of the dilator body 100 has a main body portion 115 having an outer diameter D2 that is approximately the same as the outer diameter D1 of the intermediate region 130, and a tapered portion 117 that extends from the tip of the main body portion 115 toward the tip side and has an outer diameter that decreases from the base end side toward the tip side, and the foamed resin portion 140 is located so as to straddle the boundary between the tip of the main body portion 115 and the base end 117b of the tapered portion 117, and the tip 141 of the foamed resin portion 140 is located further toward the tip side than the base end 117b of the tapered portion 117.

[0135] The distal region 110 of the dilator body 100 includes a tapered portion 117. The outer diameter of the distal region 110 decreases from the base end 117b of the tapered portion 117 to the distal end 117a of the tapered portion 117. This improves the insertability of the distal region 110 of the dilator body 100 into a biological lumen. Furthermore, the diameter d1 of the lumen 105 of the dilator body 100 is approximately constant along the axial direction. Therefore, the wall thickness 106 of the distal region 110 decreases from the base end 117b of the tapered portion 117 to the distal end 117a of the tapered portion 117. This improves the flexibility of the dilator body 100 near the distal end 101 of the distal region 110, improving its followability to the guidewire.

[0136] The dilator body 100 has a foamed resin portion 140 arranged from a position distal to the base end 117b of the tapered portion 117 to the main body portion 115, which is located proximal to the base end 117b of the tapered portion 117. As a result, the dilator body 100 has a gentle difference in rigidity at the boundary between the base end 117b of the tapered portion 117 and the tip of the main body portion 115. This makes it possible for the dilator body 100 to prevent buckling near the boundary between the base end 117b of the tapered portion 117 and the tip of the main body portion 115, which would be caused by the difference in rigidity at the boundary between the base end 117b of the tapered portion 117 and the tip of the main body portion 115. Therefore, the dilator body 100 can improve the insertability of the tip region 110 into a biological lumen. Furthermore, the dilator body 100 has a foamed resin portion 140 provided in a predetermined region from the tip of the main body portion 115 to a position more proximal than the base end of the main body portion 115 (a position more proximal than the tip of the intermediate region 130). In other words, the dilator body 100 has the foamed resin portion 140 in the region from the tip of the main body portion 115 to the base end of the main body portion 115. As a result, the amount of resin material in the wall thickness 106 of the main body portion 115 of the dilator body 100 is reduced. This improves the flexibility and pliability of the portion of the tip region 110 where the main body portion 115 is located. This effectively improves the followability of the tip region 110 of the dilator body 100 to the guidewire.

[0137] The dilator body 100 further has non-foamed resin sections 150A, 150B that do not contain fine bubbles 145 inside the wall thickness 106 of the dilator body 100, and the non-foamed resin sections 150A, 150B are located in the longitudinal direction of the dilator body 100 in the region between the tip of the tip region 110 and the tip 141 of the foamed resin section 140, and in the region between the base end 143 of the foamed resin section 140 and the base end of the dilator body 100.

[0138] As described above, the dilator body 100 includes a first non-foamed resin portion 150A located in the region between the tip of the tip region 110 and the tip 141 of the foamed resin portion 140. The first non-foamed resin portion 150A does not contain microbubbles 145 inside the wall thickness 106 of the dilator body 100, and therefore the wall thickness 106 of the dilator body 100 increases in volume. Therefore, when the dilator body 100 is configured so that a contrast agent is contained in the wall thickness 106 of the dilator body 100, a predetermined level of contrast can be ensured near the tip of the tip region 110. Furthermore, as described above, the dilator body 100 does not have a foamed resin portion 140 containing fine bubbles 145 in the region between the base end 143 of the foamed resin portion 140 and the base end of the dilator body 100, and therefore has appropriate rigidity in the region on the base end side in the longitudinal direction of the dilator body 100 (for example, the region from a position proximal to the longitudinal tip of the intermediate region 130 to near the base end of the base end region 120). This allows a pushing force to be firmly transmitted from the proximal side (base end side) of the catheter assembly 1 toward the tip end side when inserting the catheter assembly 1 into a biological lumen. This allows the surgeon or the like to smoothly insert the catheter assembly 1 into a biological lumen.

[0139] Furthermore, the tip 141 of the foamed resin portion 140 is located closer to the base end than the central portion 117 c of the tapered portion 117 .

[0140] In the region distal to the central portion 117c of the tapered portion 117, the rate of decrease in the wall thickness 106 relative to the wall thickness 106 of the main body portion 115 is greater than in the region proximal to the central portion 117c of the tapered portion 117. As described above, the tip 141 of the foamed resin portion 140 is located proximal to the central portion 117c of the tapered portion 117, and therefore, the flexibility of the dilator body 100 can be prevented from becoming excessively high in the region distal to the central portion 117c of the tapered portion 117. Therefore, when the dilator body 100 is inserted into a biological lumen, buckling can be prevented from occurring in the region distal to the central portion 117c of the tapered portion 117. Furthermore, the dilator body 100 is configured such that the foamed resin portion 140 straddles the boundary between the tip of the main body 115 and the base end 117b of the tapered portion 117, and the tip 141 of the foamed resin portion 140 is located closer to the base end than the central portion 117c of the tapered portion 117. Therefore, the flexibility of the dilator body 100 is suitably increased near the base end 117b of the tapered portion 117 (near the tip of the main body 115), while preventing the flexibility of the dilator body 100 from becoming excessively high in the region closer to the tip than the central portion 117c of the tapered portion 117.

[0141] The catheter body 310 also has a first region 320A and a second region 320B located on the base end side of the first region 320A and having a reinforcing member 330 inside the wall thickness 316 of the catheter body 310, and the first region 320A does not have the reinforcing member 330, and the base end 143 of the foamed resin portion 140 is located in the second region 320B of the catheter body 310 in the inserted state.

[0142] As described above, the catheter body 310 has the reinforcing member 330 disposed in the second region 320B of the catheter body 310. Therefore, in the inserted state, the catheter assembly 1 has greater rigidity at the position where the second region 320B of the catheter body 310 and the dilator body 100 overlap in the longitudinal direction than at the position where the first region 320A of the catheter body 310 and the dilator body 100 overlap in the longitudinal direction. In the dilator body 100, the foamed resin section 140 is disposed so as to straddle the boundary between the distal region 110 and the intermediate region 130. In this configuration, if the base end 143 of the foamed resin section 140 were disposed only in the position corresponding to the first region 320A (if the foamed resin section 140 did not extend to the position corresponding to the second region 320B), the catheter assembly 1 would have an even greater difference in rigidity between the portion corresponding to the first region 320A and the portion corresponding to the second region 320B in the inserted state. In the catheter assembly 1, in the inserted state, the base end 143 of the foamed resin section 140 is located in the second region 320B of the catheter body 310. Therefore, the catheter assembly 1 can prevent the difference in rigidity between the portion corresponding to the first region 320A and the portion corresponding to the second region 320B from becoming excessively large.

[0143] Furthermore, the cross-sectional area of ​​the wall thickness 106 of the dilator body 100 at a position in the main body portion 115 corresponding to the foamed resin portion 140 is smaller than the cross-sectional area of ​​the wall thickness 106 of the dilator body 100 at a position corresponding to the second non-foamed resin portion 150B of the intermediate region 130, and is larger than the cross-sectional area of ​​the wall thickness 106 of the dilator body 100 at a position corresponding to the central portion 117c of the tapered portion 117.

[0144] The dilator body 100 configured as described above has the following relationship: flexibility of the central portion 117c of the tapered portion 117 and the region distal to the central portion 117c of the tapered portion 117 > flexibility of the portion of the main body 115 where the foamed resin portion 140 is provided > flexibility of the portion of the intermediate region 130 where the second non-foamed resin portion 150B is provided. Also, as described above, the tip 141 of the foamed resin portion 140 is located closer to the base end than the central portion 117c of the tapered portion 117. Therefore, the dilator body 100 is configured so that the flexibility of the portion of the main body 115 where the foamed resin portion 140 is provided is smaller than the flexibility of the central portion 117c of the tapered portion 117 and the region distal to the central portion 117c of the tapered portion 117. That is, the portion of the main body 115 where the foamed resin portion 140 is provided has higher rigidity than the central portion 117c of the tapered portion 117 and the region distal to the central portion 117c of the tapered portion 117. Therefore, when the distal region 110 of the dilator body 100 is inserted into a biological lumen, it is possible to prevent the portion of the main body 115 where the foamed resin portion 140 is provided from deforming and increasing the insertion resistance of the dilator body 100. Furthermore, because the central portion 117c of the tapered portion 117 and the region distal to the central portion 117c of the tapered portion 117 do not have the foamed resin portion 140, it is also possible to prevent the flexibility of the central portion 117c of the tapered portion 117 and the region distal to the central portion 117c of the tapered portion 117 from becoming excessively high. Therefore, when the distal region 110 of the dilator body 100 is inserted into a biological lumen, deformation such as buckling can be suppressed in the central portion 117c of the tapered portion 117 and in the region distal to the central portion 117c of the tapered portion 117. In addition, by providing the above-described relationship in flexibility, the dilator body 100 is configured so that the flexibility of the portion of the main body 115 where the foamed resin portion 140 is provided is greater than the flexibility of the portion of the intermediate region 130 where the second non-foamed resin portion 150B is provided. In other words, the dilator body 100 is configured so that the portion of the main body 115 where the foamed resin portion 140 is provided and the portion of the intermediate region 130 where the foamed resin portion 140 is provided are more flexible than the portion of the intermediate region 130 where the second non-foamed resin portion 150B is provided.Therefore, in the inserted state of the catheter assembly 1, the difference in rigidity is reduced from the portion of the main body 115 where the foamed resin portion 140 is provided to the portion of the intermediate region 130 where the second non-foamed resin portion 150B is provided. As a result, in the inserted state of the catheter assembly 1, the insertability into a biological lumen is improved.

[0145] Furthermore, the cross-sectional area of ​​the wall thickness 106 of the dilator body 100 at a position in the main body 115 corresponding to the foamed resin portion 140 is approximately the same as or smaller than the cross-sectional area of ​​the position 118 corresponding to the first non-foamed resin portion 150A located between the tip 141 of the foamed resin portion 140 and the central portion 117c of the tapered portion 117.

[0146] In the dilator body 100, the foamed resin section 140 is positioned so as to straddle the boundary between the tip of the main body section 115 and the base end 117b of the tapered section 117, and the tip 141 of the foamed resin section 140 is positioned closer to the base end than the central section 117c of the tapered section 117. When this configuration is adopted, position 118 corresponding to the first non-foamed resin section 150A located between the central section 117c of the tapered section 117 and the tip 141 of the foamed resin section 140 is located at the base end of the first non-foamed resin section 150A adjacent to the tip 141 of the foamed resin section 140, and because this is an area near the boundary between the foamed resin section 140 and the first non-foamed resin section 150A, this is a portion to which a load is applied when the tip region 110 of the dilator body 100 is inserted into a biological lumen. Therefore, if the position 118 is configured to be more flexible (more pliable) than the portion of the main body 115 where the foamed resin portion 140 is provided (the tip of the main body 115), the load applied when inserting the tip region 110 of the dilator main body 100 into the biological lumen may cause the position 118 to deform, which may reduce the insertability of the dilator main body 100 into the biological lumen. In the dilator body 100, the flexibility of the position 118 is configured to be approximately the same as or less than the flexibility of the portion of the main body 115 where the foamed resin section 140 is provided. This reduces the load that occurs at the position corresponding to the first non-foamed resin section 150A located between the center 117c of the tapered section 117 and the tip 141 of the foamed resin section 140 (the region near the boundary between the foamed resin section 140 and the non-foamed resin section) when the dilator body 100 is inserted into a biological lumen, thereby preventing deformation at the position 118. This improves the insertability of the dilator body 100 into a biological lumen. Furthermore, when the flexibility of the position 118 is configured to be substantially the same as the flexibility of the portion of the main body 115 where the foamed resin portion 140 is provided, it is possible to prevent the flexibility of the position 118 from being excessively small compared to the flexibility of the portion of the main body 115 where the foamed resin portion 140 is provided. Therefore, the dilator body 100 can prevent an excessive difference in rigidity from occurring in the region from the center portion 117c of the tapered portion 117 to the portion of the main body 115 where the foamed resin portion 140 is provided.Therefore, when the dilator body 100 is inserted into a biological lumen, the dilator body 100 can effectively prevent excessive bending at the position 118, causing buckling or the like. Furthermore, the flexibility of the dilator body 100 is greater than the flexibility of the portion of the main body 115 where the foamed resin portion 140 is provided, and greater than the flexibility of the portion of the intermediate region 130 where the second non-foamed resin portion 150B is provided. Additionally, as described above, the tip 141 of the foamed resin portion 140 is located closer to the base end than the central portion 117c of the tapered portion 117. Therefore, the dilator body 100 is configured so that the flexibility of the portion of the main body 115 where the foamed resin portion 140 is provided is less than the flexibility of the central portion 117c of the tapered portion 117 and the region distal to the central portion 117c of the tapered portion 117. That is, the portion of the main body 115 where the foamed resin portion 140 is provided has higher rigidity than the central portion 117c of the tapered portion 117 and the region distal to the central portion 117c of the tapered portion 117. Therefore, when the distal region 110 of the dilator body 100 is inserted into a biological lumen, it is possible to prevent the portion of the main body 115 where the foamed resin portion 140 is provided from deforming and increasing the insertion resistance of the dilator body 100. Furthermore, because the central portion 117c of the tapered portion 117 and the region distal to the central portion 117c of the tapered portion 117 do not have the foamed resin portion 140, it is also possible to prevent the flexibility of the central portion 117c of the tapered portion 117 and the region distal to the central portion 117c of the tapered portion 117 from becoming excessively high. Therefore, when the distal region 110 of the dilator body 100 is inserted into a biological lumen, it is possible to prevent deformation such as buckling from occurring in the central portion 117c of the tapered portion 117 and in the region distal to the central portion 117c of the tapered portion 117. In addition, by providing the above-described relationship in terms of flexibility, the dilator body 100 is configured so that the flexibility of the portion of the main body 115 where the foamed resin portion 140 is provided is greater than the flexibility of the portion of the intermediate region 130 where the second non-foamed resin portion 150B is provided.That is, in the dilator body 100, the portion of the main body 115 where the foamed resin portion 140 is provided and the portion of the intermediate region 130 where the foamed resin portion 140 is provided are configured to be more flexible than the portion of the intermediate region 130 where the second non-foamed resin portion 150B is provided. Therefore, in the inserted state of the catheter assembly 1, the difference in rigidity from the portion of the main body 115 where the foamed resin portion 140 is provided to the portion of the intermediate region 130 where the second non-foamed resin portion 150B is provided is alleviated. For these reasons, the catheter assembly 1 has improved insertability into a biological lumen in the inserted state.

[0147] The dilator body 100 also has a first skin layer 107 at a position corresponding to at least the foamed resin portion 140 on the inner surface 100 a that forms the lumen 105 of the dilator body 100 .

[0148] The first skin layer 107 prevents the fine bubbles 145 contained in the foamed resin portion 140 from forming in a manner that is continuous with the inner surface 100a. Therefore, the dilator body 100 can prevent the fine bubbles 145 from being exposed on the inner surface 100a at the position where the foamed resin portion 140 is provided, thereby preventing unevenness from being formed on the inner surface 100a. By providing the first skin layer 107, the dilator body 100 has a smooth inner surface 100a. This prevents the guidewire inserted into the lumen 105 of the dilator body 100 from getting caught on such unevenness, which could impair the insertability of the guidewire.

[0149] The dilator body 100 also has a second skin layer 108 at least at a position on the outer surface 100b corresponding to the foamed resin portion 140.

[0150] The second skin layer 108 prevents the fine bubbles 145 contained in the foamed resin portion 140 from forming a contiguous region with the outer surface 100b. This prevents the fine bubbles 145 from being exposed on the outer surface 100b at the location where the foamed resin portion 140 is provided, thereby preventing the formation of irregularities on the outer surface 100b. By providing the second skin layer 108, the dilator body 100 has a smooth outer surface 100b. This prevents the dilator body 100, in the inserted state, from forming a clearance between the outer surface 100b of the dilator body 100 and the inner surface of the catheter body 310, and from applying stress to the inner wall of the biological lumen (e.g., a blood vessel wall) due to the irregularities.

[0151] <Modifications> Next, modifications of the above-described embodiment will be described. In the description of the modifications, duplicated descriptions of the contents, structures, members, etc. that have already been described will be omitted.

[0152] 7 , in this modification, a tip member 318 having radiopaque properties is disposed at a position corresponding to the tip portion 311 of the catheter 300. The tip portion 311 is made of, for example, a resin material softer than the resin material of the wall thickness 316 of the catheter body 310.

[0153] The tip member 318 may be configured, for example, to have a tapered portion in which the outer diameter decreases toward the tip side. The tip member 318 may be configured, for example, from a material in which a resin material is mixed with any of the various metal materials exemplified as the contrast agent material described above.

[0154] When the catheter assembly 1 is inserted, the contrast properties of the various parts are as follows:

[0155] The catheter assembly 1 is configured so that, in the inserted state, the contrastability of the region where the tip member 318 is located (the intermediate region 130 and a portion of the distal end of the first region 320A) is higher than the contrastability of the region where the foamed resin part 140 is provided in the tip region 110 (the region from the distal end of the foamed resin part 140 to the proximal end of the tip region 110). Furthermore, the catheter assembly 1 is configured so that, in the inserted state, the contrastability of the region where the tip member 318 is located (the intermediate region 130 and a portion of the distal end of the first region 320A) is higher than the contrastability of the region where the foamed resin part 140 is provided in the intermediate region 130, which is located between the proximal end of the tip member 318 and the distal end of the second region 320B. Therefore, under X-ray imaging, the catheter assembly 1 is projected in contrast around the tip member 318, with a low contrast region-high contrast region-low contrast region shading from the distal end of the tip region 110 toward the intermediate region 130. By checking this contrast under X-ray imaging, the surgeon or the like can more clearly grasp the position of the tip of the catheter main body 310.

[0156] Furthermore, since the dilator body 100 has the first non-foamed resin portion 150A located in the region between the tip of the tip region 110 and the tip 141 of the foamed resin portion 140, contrast can be sufficiently ensured near the tip of the tip region 110 (near the tip 117a of the tapered portion 117). This allows the surgeon or the like to grasp the position of the tip of the dilator body 100 under X-ray images.

[0157] The catheter assembly according to the present invention has been described above through the embodiments, but the present invention is not limited to the content described in this specification and can be modified as appropriate based on the description of the claims.

[0158] The structure of each part and the arrangement of components described in the specification may be changed as appropriate, and the use of additional components described in the drawings may be omitted or other additional components may be used as appropriate.

[0159] This application is based on Japanese Patent Application No. 2024-107455, filed on July 3, 2024, the disclosure of which is incorporated herein by reference in its entirety.

[0160] 1 Catheter assembly 10 Dilator 100 Dilator body 100a Inner surface of dilator body 100b Outer surface of dilator body 101 Distal end portion of dilator body 101a Distal end opening 103 Base end portion of dilator body 103a Base end opening 105 Lumen of dilator body 106 Wall thickness of dilator body 107 First skin layer 108 Second skin layer 110 Distal end region 115 Main body portion 117 Tapered portion 117a Distal end of tapered portion 117b Base end of tapered portion 117c Central portion of tapered portion 120 Base end region 130 Intermediate region 140 Foamed resin portion 141 Distal end of foamed resin portion 143 Base end of foamed resin portion 145 Group of fine bubbles 150A First non-foamed resin portion 150B Second non-foamed resin portion 200 Dilator hub 207 Opening of dilator hub 300 Catheter 310 Catheter body 311 Distal end of catheter body 311a Distal end opening of catheter body 313 Base end of catheter body 313a Base end opening of catheter body 315 Lumen of catheter body 316 Wall thickness of catheter body 318 Distal end member 320A First region 320B Second region 330 Reinforcing member 340 Catheter hub d1 Diameter of lumen of dilator body D1 Outer diameter of intermediate region D2 Outer diameter of main body c1 Central axis of dilator body

Claims

1. A catheter assembly comprising: a dilator comprising: a dilator body having a lumen penetrating between its distal and proximal ends; and a dilator hub connected to the proximal end of the dilator body and having an opening communicating with the lumen of the dilator body; and a catheter body having a lumen into which the dilator body can be inserted; and a catheter hub connected to the proximal end of the catheter body and connectable to the dilator hub, wherein the dilator body has a distal region, a proximal region, and an intermediate region located between the distal region and the proximal region, and the distal region protrudes further distally than the distal end of the catheter body when the dilator body is inserted through the lumen of the catheter body, and the dilator body has a foamed resin portion containing fine bubbles within the wall thickness of the dilator body so as to straddle the boundary between the proximal end of the distal region and the distal end of the intermediate region.

2. A catheter assembly as described in claim 1, wherein the tip region has a main body portion having an outer diameter substantially the same as the outer diameter of the intermediate region, and a tapered portion extending from the tip of the main body portion toward the tip side and having an outer diameter that decreases from the base end toward the tip side, and the foamed resin portion is located so as to straddle the boundary between the tip of the main body portion and the base end of the tapered portion, and the tip of the foamed resin portion is located closer to the tip side than the base end of the tapered portion.

3. The catheter assembly according to claim 2, wherein the dilator body further has a non-foamed resin section that does not contain the fine bubbles within the thickness of the dilator body, and the non-foamed resin section is located in the longitudinal direction of the dilator body in a region between the tip of the tip region and the tip of the foamed resin section, and in a region between the base end of the foamed resin section and the base end of the dilator body.

4. A catheter assembly according to claim 3, wherein the tip of the foamed resin portion is located closer to the base end than the center of the tapered portion.

5. A catheter assembly as described in claim 1, wherein the catheter body has a first region and a second region located on the proximal side of the first region and having a reinforcing member inside the thickness of the catheter body, the first region does not have the reinforcing member, and the proximal end of the foamed resin portion is located in the second region when the dilator body is inserted through the lumen of the catheter body.

6. A catheter assembly as described in claim 4, wherein the cross-sectional area of ​​the wall thickness of the dilator body at a position in the main body corresponding to the foamed resin portion is smaller than the cross-sectional area of ​​the wall thickness of the dilator body at a position corresponding to the non-foamed resin portion in the intermediate region, and is larger than the cross-sectional area of ​​the wall thickness of the dilator body at a position corresponding to the central portion of the tapered portion.

7. A catheter assembly as described in claim 4, wherein the cross-sectional area of ​​the wall thickness of the dilator body at a position in the main body corresponding to the foamed resin portion is approximately the same as or smaller than the cross-sectional area at a position corresponding to the non-foamed resin portion located between the tip of the foamed resin portion and the central portion of the tapered portion.

8. A catheter assembly according to claim 1, wherein the dilator body has a first skin layer at least at a position corresponding to the foamed resin portion on the inner surface forming the lumen of the dilator body.

9. A catheter assembly according to claim 1, wherein the dilator body has a second skin layer on the outer surface at least at a position corresponding to the foamed resin portion.

Images