Catheter and catheter assembly

Abstract

This catheter (12) comprises a flexible catheter body (121). The catheter body (121) has a distal end part (20) that has a first region (261) and a second region (262) that is formed from a material harder than the first region (261) and functions as a reinforcing layer. The catheter body (121) has a thinnest part (241) at a position adjacent to a lumen (16) in the eccentric direction of the lumen (16) relative to the catheter body (121), the thinnest part (241) having the smallest radial thickness (T) of a peripheral wall part (18) of the catheter body (121). The second region (262) is disposed at least in the thinnest part (241).

Description

Catheter and catheter assembly

[0001] The present disclosure relates to catheters and catheter assemblies.

[0002] WO 2018 / 164235 discloses a catheter that is rigid when inserted into a blood vessel and becomes flexible when placed in a living body.

[0003] International Publication No. 2018 / 164235

[0004] When the tip of the catheter is placed in a living body and suction is performed using a suction device connected to the base end of the catheter, negative pressure is generated within the catheter, and this negative pressure can cause the tip of the catheter to elastically deform and become blocked. Therefore, it is desirable to prevent the tip of the catheter from becoming blocked during suction while maintaining the flexibility of the catheter when placed in a living body.

[0005] The present disclosure aims to solve the above-mentioned problems.

[0006] (1) A first aspect of the present disclosure is a hollow cylindrical catheter including a flexible catheter body, the catheter body having a tip portion with a tip opening formed therein, a central axis of a lumen of the catheter body being eccentric with respect to the central axis of the catheter body, the tip portion of the catheter body having a first region and a second region formed of a material harder than the first region and functioning as a reinforcing layer, the catheter body further having a thinnest portion, where the radial thickness of the peripheral wall of the catheter body is smallest, located adjacent to the lumen in the eccentric direction of the lumen relative to the catheter body, and the second region being provided in at least the thinnest portion.

[0007] According to this catheter, by providing a relatively thin portion (thinnest portion) at the tip of the catheter body, it is possible to control the direction in which the catheter body collapses due to the negative pressure generated during suction (the position that serves as the base point for elastic deformation). Therefore, by providing a second region in the thinnest portion, it is possible to maintain the flexibility of the catheter body while effectively suppressing the collapse of the tip of the catheter body during suction. This makes it possible to realize a catheter that is easy to use.

[0008] (2) In the catheter described in (1) above, the second region may be disposed along the lumen of the catheter body in a cross section perpendicular to the axial direction of the catheter body.

[0009] With this configuration, the second region can effectively increase the strength of the thinnest part and its vicinity along the circumferential direction of the catheter body.

[0010] (3) In the catheter described in (1) or (2) above, the first region may be formed to be transparent or translucent, and the second region may be formed from a radiopaque contrast material.

[0011] With this configuration, the inside of the catheter body can be effectively viewed from the outside of the catheter body through the first region, and when the catheter is inserted into a living body, the position of the tip of the catheter, including the second region, can be effectively confirmed using a radioscopic image.

[0012] (4) In the catheter according to (1) or (2) above, the second region may include a plurality of reinforcing portions spaced apart from one another along the circumferential direction of the catheter body.

[0013] With this configuration, the second region is made up of a plurality of reinforcing parts, and by appropriately changing the number and arrangement of the reinforcing parts, the strength of the second region can be effectively adjusted.

[0014] (5) A second aspect of the present disclosure is a catheter assembly including a flexible, hollow, cylindrical catheter body, a catheter hub connected to a base end of the catheter body and to which a suction device can be connected, an inner needle inserted into the catheter body, and the needle hub connected to the base end of the inner needle, wherein the catheter body has a tip end portion with a tip opening formed therein, the central axis of the lumen of the catheter body is eccentric with respect to the central axis of the catheter body, the tip end portion of the catheter body has a first region and a second region formed of a material harder than the first region and functioning as a reinforcing layer, the catheter body further has a thinnest part, where the radial thickness of the peripheral wall of the catheter body is smallest, located adjacent to the lumen in the eccentric direction of the lumen relative to the catheter body, and the second region is provided in at least the thinnest part.

[0015] According to this catheter assembly, by providing a relatively thin portion (thinnest portion) at the tip of the catheter body, it is possible to control the direction in which the catheter body collapses due to negative pressure generated during suction (the position that serves as the base point for elastic deformation). Therefore, by providing the second region in the thinnest portion, it is possible to maintain the flexibility of the catheter body while effectively suppressing collapse of the tip of the catheter body during suction. This makes it possible to realize a catheter assembly that is easy to use.

[0016] (6) In the catheter assembly described in (5) above, the second region may be disposed along the lumen of the catheter body in a cross section perpendicular to the axial direction of the catheter body.

[0017] With this configuration, the second region can effectively increase the strength of the thinnest part and its vicinity along the circumferential direction of the catheter body.

[0018] (7) In the catheter assembly described in (5) or (6) above, the first region may be formed to be transparent or translucent, and the second region may be formed from a radiopaque contrast material.

[0019] This configuration allows the inside of the catheter body to be effectively viewed from the outside of the catheter body through the first region, and when the catheter is inserted into a living body, the position of the tip of the catheter, including the second region, can be effectively confirmed using a radioscopic image.

[0020] According to the present disclosure, the central axis of the lumen of the catheter body is eccentric with respect to the central axis of the catheter body, and by providing a thinnest portion with the smallest radial thickness at the tip of the catheter body, it is possible to control the direction in which the catheter body collapses due to negative pressure generated during suction of the catheter (the position that serves as the base point for elastic deformation).As a result, by providing a second region in the thinnest portion, it is possible to maintain the flexibility of the catheter body while effectively suppressing collapse of the tip of the catheter body during suction by the second region.

[0021] FIG. 1 is an overall configuration diagram of a catheter assembly according to an embodiment of the present disclosure. FIG. 2 is an overall configuration diagram of a catheter constituting the catheter assembly of FIG. 1. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 4 is an explanatory diagram showing the catheter assembly of FIG. 1 inserted into a living body. FIG. 5 is an explanatory diagram showing the case where a suction instrument is connected to the proximal end of the catheter for suction. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. FIG. 7 is a cross-sectional view of a catheter according to a first modified example. FIG. 8 is a cross-sectional view of a catheter according to a second modified example. FIG. 9 is a cross-sectional view of a catheter according to a third modified example.

[0022] As shown in Figure 1, at least the tip of the catheter assembly 10 according to this embodiment is inserted into a living body A (see Figure 4) and a portion of the catheter assembly 10 is left indwelling within the living body A. The catheter assembly 10 is used, for example, as an indwelling needle for a peripheral artery or vein, an indwelling needle for dialysis, a peripherally inserted central venous catheter (PICC), a midline catheter, a central venous catheter (CV catheter), etc.

[0023] The catheter assembly 10 includes a hollow cylindrical catheter 12 and a needle member 14 inserted into the catheter 12. The needle member 14 includes an inner needle 141 and a needle hub 142 connected to the proximal end of the inner needle 141. As shown in Figure 4, the tip of the catheter assembly 10 including the catheter 12 is inserted subcutaneously into living body A.

[0024] As shown in Fig. 2, the catheter 12 includes a flexible catheter body 121 and a catheter hub 122 connected to the proximal end of the catheter body 121. The catheter body 121 is formed in a tubular shape with an internal lumen 16. As shown in Fig. 3, the catheter body 121 has a peripheral wall portion 18 that surrounds the lumen 16. The peripheral wall portion 18 is formed in an annular shape and is disposed radially outward from the lumen 16.

[0025] As shown in Fig. 2, the distal end portion 20 of the catheter body 121 has a distal end opening 22. The distal end opening 22 opens toward the distal end at the distal end 20 of the catheter body 121. The distal end opening 22 communicates with the lumen 16. As shown in Fig. 1, the inner needle 141 of the needle member 14 is inserted into the lumen 16. The distal end of the inner needle 141 protrudes toward the distal end from the distal end 20 of the catheter body 121. The distal end 20 of the catheter body 121 is the end that is inserted into the living body A (see Fig. 4). The outer peripheral surface of the distal end portion 20 of the catheter body 121 is formed in a tapered shape toward the distal end.

[0026] 3, the central axis C1 of the lumen 16 of the catheter body 121 (hereinafter referred to as the lumen axis C1) is radially eccentric with respect to the central axis C2 of the catheter body 121 (hereinafter referred to as the catheter axis C2). Therefore, in a cross section perpendicular to the axial direction of the catheter body 121, the lumen axis C1 and the catheter axis C2 are spaced apart from each other.

[0027] In the catheter main body 121, the lumen axis C1 is radially eccentric with respect to the catheter axis C2 by a predetermined distance L (hereinafter referred to as the eccentric distance L). When the catheter axis C2 and the lumen axis C1 of the catheter main body 121 are not eccentric and are the same (as indicated by the two-dot chain line in FIG. 3 ), and the radial thickness of the peripheral wall portion 18 is t, the eccentric distance L is within a range of 10 to 90% of the radial thickness t (0.1t≦L≦0.9t). The eccentric distance L is more preferably within a range of 10 to 50% of the radial thickness t. Optimally, the eccentric distance L is within a range of 10 to 30% of the radial thickness t. Hereinafter, the eccentric direction (X direction) of the lumen axis C1 with respect to the catheter axis C2 will also be referred to as the "eccentric direction of the lumen 16."

[0028] The radial thickness T of the peripheral wall 18 of the catheter body 121 varies in the circumferential direction of the catheter body 121. The catheter body 121 has a thinnest part 241 having the smallest radial thickness T and a thickest part 242 having the largest radial thickness T. In the cross section of the catheter body 121, the thinnest part 241 is located adjacent to the lumen 16 in the eccentric direction of the lumen 16. The thinnest part 241 has the smallest radial thickness T in the circumferential direction of the catheter body 121. In the cross section of the catheter body 121, the thinnest part 241 is the thinnest and therefore most susceptible to elastic deformation.

[0029] In the cross section of the catheter main body 121, the thickest part 242 is located adjacent to the lumen 16 in the direction opposite to the eccentric direction of the lumen 16 (the direction of arrow X). The thickest part 242 has the largest radial thickness T in the circumferential direction of the catheter main body 121. In the cross section of the catheter main body 121, the thinnest part 241 and the thickest part 242 face each other across the catheter axis C2. In the circumferential direction of the catheter main body 121, the radial thickness T of the peripheral wall part 18 gradually increases from the thinnest part 241 toward the thickest part 242.

[0030] The distal end section 20 of the catheter body 121 further includes a first region 261 and a second region 262. Specifically, the first region 261 is a region that imparts flexibility to the entire catheter body 121. The second region 262 is a region that is made of a material that is harder than the first region 261, and is a region that partially reinforces the catheter body 121 in the circumferential direction without impairing the overall flexibility of the catheter body 121.

[0031] The first region 261 is provided on the peripheral wall 18 of the catheter body 121. As shown in FIG. 2 , the first region 261 extends axially from the distal end 20 to the proximal end of the catheter body 121. The first region 261 is formed to be transparent or translucent. Examples of the material for the first region 261 include thermoplastic resin (fluororesin, ETFE), polyurethane (PU), polyvinyl chloride (PVC), silicone (SI), polyethylene (PE), and natural rubber (NR). The material for the catheter body 121 preferably has a hardness sufficient for inserting the distal end of the catheter body 121 into a living body A, and a softness sufficient for conforming to the shape of the vascular system after placement within the living body A. The first region 261 is not limited to being formed from a transparent or translucent material. For example, the first region 261 may be formed from an impermeable material.

[0032] The second region 262 constitutes a part of the peripheral wall 18 of the catheter body 121. The second region 262 is formed of a material different from that of the first region 261. As shown in FIG. 3 , the second region 262 is arranged radially alongside the first region 261 in the cross section of the catheter body 121. In the cross section perpendicular to the axial direction of the catheter body 121, the second region 262 is arranged along the lumen 16 of the catheter body 121. The cross section of the second region 262 is a continuous arc shape that follows the cross section of the catheter body 121. The second region 262 is provided inside the first region 261. Note that the second region 262 is not limited to being arranged in an arc shape along the lumen 16 of the catheter body 121. For example, the second region 262 may be formed linearly in a direction perpendicular to the eccentric direction (direction of arrow X) of the lumen axis C1.

[0033] The second region 262 is disposed at a position including at least the thinnest part 241 in the cross section of the catheter body 121. That is, when a straight line passing through the catheter axis C2 and the lumen axis C1 in the cross section of the catheter body 121 is defined as an imaginary line D, the thinnest part 241 is located on the imaginary line D. When negative pressure is generated in the lumen 16 of the catheter body 121, the distal end 20 of the catheter body 121 is most likely to collapse. For this reason, the second region 262 is provided at least in the distal end 20 of the catheter body 121. In the axial direction of the catheter body 121, the second region 262 may be provided only in the distal end 20 of the catheter body 121, or may be provided from the distal end 20 to the proximal end of the catheter body 121. Here, a case where the second region 262 extends axially from the distal end 20 to the proximal end of the catheter body 121 will be described.

[0034] The second region 262 is formed of a material harder than the first region 261. The second region 262 is formed, for example, of a contrast material that is radiopaque. The contrast material is, for example, barium sulfate. The second region 262 is formed in the axial direction of the catheter main body 121 by extrusion molding together with the catheter main body 121. Note that the second region 262 is not limited to being formed of a contrast material. For example, the second region 262 may be formed of a material that is transmissive to radiation.

[0035] In the cross section of the catheter body 121, the cross-sectional area of ​​the second region 262 is smaller than the cross-sectional area of ​​the first region 261. The second region 262 is provided between the outer peripheral surface of the circumferential wall 18 of the catheter body 121 and the lumen 16. The second region 262 extends on both sides of the circumferential direction of the catheter body 121, centered on the thinnest part 241. In the circumferential direction of the catheter body 121, the circumferential length of the second region 262 is, for example, 25% to 40% of the circumferential length of the first region 261. By providing the second region 262 in the thinnest part 241 of the catheter body 121, the strength of the thinnest part 241 is increased. The second region 262 functions as a reinforcing layer for the catheter body 121. The radial thickness of the second region 262 is, for example, smaller than the radial thickness of the first region 261. The radial thickness of the second region 262 is approximately constant along the extension direction of the second region 262. The radial thickness of second region 262 does not have to be constant along the extension direction of second region 262. For example, the radial thickness of second region 262 may be greatest at a portion located at thinnest part 241 and gradually decrease in the direction away from thinnest part 241.

[0036] In order to improve visibility under radioscopy, a contrast layer may be formed on the outer periphery of the catheter body 121 .

[0037] The second region 262 is not limited to being provided between the lumen 16 of the catheter body 121 and the outer peripheral surface of the circumferential wall 18. For example, a portion of the second region 262 may be exposed to at least one of the inner and outer peripheral surfaces of the circumferential wall 18 of the catheter body 121. In this case, the second region 262 is provided so as not to protrude radially inward from the inner peripheral surface of the catheter body 121, and not to protrude radially outward from the outer peripheral surface.

[0038] The catheter body 121 is formed, for example, by extrusion molding along the axial direction. During extrusion molding, the central axis of an outer mold (not shown) and the central axis of an inner mold (not shown) inserted into the outer mold can be offset by an eccentricity distance to produce a catheter body 121 in which the catheter axis C2 and the lumen axis C1 are radially eccentric in the cavity between the outer mold and the inner mold. When the first region 261 and the second region 262 are manufactured by extrusion molding of the catheter body 121, it is preferable that the viscosity of the material of the first region 261 and the viscosity of the material of the second region 262 are approximately the same.

[0039] As shown in Figure 2, the catheter hub 122 is formed in a cylindrical shape with a hub lumen 28. The catheter hub 122 has a proximal end opening 30 that opens in the proximal direction. The proximal end of the catheter body 121 is connected to the distal end of the catheter hub 122. The hub lumen 28 opens at the proximal end of the catheter body 121. The hub lumen 28 and the lumen 16 of the catheter body 121 communicate with each other. As shown in Figure 1, the needle hub 142 of the needle member 14 is inserted into the proximal end opening 30 of the catheter hub 122. When the needle member 14 is removed from the catheter 12, a suction instrument 40 can be connected to the proximal end opening 30 of the catheter hub 122 (see Figure 5).

[0040] 5, the suction instrument 40 is, for example, a syringe having a cylindrical body 42, a nozzle portion 44 formed at the tip of the cylindrical body 42 and opening, and a gasket (not shown) disposed within the cylindrical body 42 and slidable in the axial direction of the cylindrical body 42. The nozzle portion 44 of the suction instrument 40 is connectable to the base end of the catheter hub 122. However, the suction instrument 40 is not limited to a syringe.

[0041] When the repulsive force of the catheter main body 121 is measured using the test method disclosed in WO 2018 / 164235, in a test in a dry state at 25°C, it is preferable to set the cross-sectional area of ​​the second region 262 relative to the catheter main body 121 so that the maximum value M1 of the first repulsive force when the catheter 12 is pushed 1.5 mm in air is 0.10 N or more, the maximum value M2 of the second repulsive force when the catheter 12 is pushed 1.5 mm in warm water is within the range of 0.01 N to 0.25 N, and the maximum value M2 of the second repulsive force relative to the maximum value M1 of the first repulsive force is 3.5 or more. Furthermore, it is preferable to set the cross-sectional area of ​​the second region 262 relative to the catheter main body 121 so that the maximum value M3 of the third repulsive force when the catheter 12 is pushed 1.5 mm in warm water and then held for 5 minutes without changing the pushing distance is 0.027 N or less.

[0042] Specifically, in the cross section of the catheter main body 121, the cross-sectional area of ​​the second region 262 is 70% or less of the cross-sectional area of ​​the first region 261. It is preferable that the cross-sectional area of ​​the second region 262 is 50% or less of the cross-sectional area of ​​the first region 261. Furthermore, it is more preferable that the cross-sectional area of ​​the second region 262 is 30% or less of the cross-sectional area of ​​the first region 261.

[0043] The repulsive force of the second region 262 is greater than the repulsive force of the catheter body 121. For example, the repulsive force of the second region 262 is 1.2 times or more the repulsive force of the catheter body 121.

[0044] Next, a description will be given of the case where the catheter assembly 10 is placed in the living body A. The case where the distal end portion 20 of the catheter 12 is placed in the blood vessel BV will be described below.

[0045] As shown in FIG. 4 , the tip of the inner needle 141 of the catheter assembly 10 is inserted into the skin of living body A. The tip of the inner needle 141 of the needle member 14 is inserted into the blood vessel BV, and the tip portion 20 of the catheter main body 121 is inserted into the blood vessel BV. The catheter main body 121 has a predetermined hardness, making it easy to insert into living body A. The tip portion 20 of the catheter main body 121 is inserted into the blood vessel BV of living body A and left there. The tip opening 22 of the catheter main body 121 opens within the blood vessel BV. Inside living body A, the first region 261 of the catheter main body 121 is warmed by the body temperature of living body A, softens, and conforms to the shape of the blood vessel BV. The user then pulls the needle member 14 out of the catheter 12 in the proximal direction. Note that the process of removing the needle member 14 from the catheter 12 is not limited to the case where the catheter main body 121 conforms to the shape of the blood vessel BV of living body A before the needle member 14 is removed from the catheter 12. For example, after the needle member 14 is removed from the catheter 12, the catheter body 121 may be adapted to conform to the shape of the blood vessel BV of the living body A.

[0046] After the placement of the catheter body 121 is completed, the nozzle portion 44 of the suction instrument 40 is connected to the proximal opening 30 of the catheter hub 122, as shown in Figure 5. This places the cylindrical body 42 of the suction instrument 40 in communication with the hub lumen 28.

[0047] When the user moves the gasket (not shown) of the suction device 40 in the proximal direction, the suction device 40 generates negative pressure in the hub lumen 28 of the catheter hub 122. The negative pressure generated in the hub lumen 28 creates negative pressure in the lumen 16 of the catheter body 121.

[0048] This negative pressure causes blood B to be sucked into the lumen 16 through the tip opening 22 of the catheter body 121. The blood B is sucked along the lumen 16 of the catheter body 121 into the hub lumen 28 and introduced into the barrel 42 of the suction device 40.

[0049] At this time, pulling the gasket of the suction instrument 40 toward the proximal end generates a sudden negative pressure inside the cylindrical body 42 of the suction instrument 40, which in turn generates a relatively large negative pressure instantaneously in the hub lumen 28 of the catheter hub 122 and the lumen 16 of the catheter body 121. The large negative pressure in the lumen 16 of the catheter body 121 exerts a radially inward suction force on the distal end 20 of the catheter body 121. For example, if the second region 262 is not provided, as shown by the two-dot chain line in FIG. 3 , the catheter body 121 attempts to elastically deform toward the imaginary line D, with the thinnest part 241 of the catheter body 121 as the base point and an imaginary line D passing through the lumen axis C1 and the catheter axis C2 as the center, into a substantially elliptical cross-sectional shape. In other words, the catheter body 121 attempts to elastically deform substantially symmetrically about the imaginary line D.

[0050] In contrast, by providing the second region 262 in the thinnest part 241, elastic deformation of the thinnest part 241 is suppressed, and accordingly, elastic deformation of the catheter main body 121 from the thinnest part 241 is suppressed. The flexible first region 261 is suppressed from being significantly elastically deformed by negative pressure. Therefore, the cross-sectional shape of the catheter main body 121 is suppressed from being significantly changed by negative pressure generated in the catheter main body 121 (see FIG. 6 ), and the tip opening 22 is maintained open without being blocked.

[0051] This embodiment has the following advantages.

[0052] As shown in Fig. 2, the distal end portion 20 of the catheter main body 121 of the catheter 12 has a first region 261 and a second region 262 that is formed of a harder material than the first region 261 and functions as a reinforcing layer. As shown in Fig. 3, the lumen axis C1 (central axis) of the lumen 16 of the catheter main body 121 is radially eccentric with respect to the catheter axis C2 (central axis) of the catheter main body 121, and the catheter main body 121 has a thinnest portion 241 where the radial thickness T of the peripheral wall portion 18 is smallest. The second region 262 is provided in at least the thinnest portion 241.

[0053] According to this configuration, by providing a relatively thin portion (thinnest portion 241) in the tip portion 20 of the catheter body 121, it is possible to control the direction in which the catheter body 121 collapses (the position that serves as the base point for elastic deformation) due to the negative pressure generated when the catheter 12 is suctioned. Therefore, by providing the second region 262 in the thinnest portion 241, it is possible to maintain the flexibility of the catheter body 121, while the second region 262 effectively suppresses the collapse of the tip portion 20 of the catheter body 121 when suctioned. This makes it possible to realize a catheter 12 that is easy to use.

[0054] In a cross section perpendicular to the axial direction of the catheter body 121, the second region 262 is disposed along the lumen 16 of the catheter body 121. According to this configuration, the second region 262 can effectively increase the strength of the thinnest part 241 and its vicinity along the circumferential direction of the catheter body 121.

[0055] The first region 261 is formed to be transparent or translucent, and the second region 262 is formed from a radiopaque contrast material. With this configuration, the interior of the catheter main body 121 can be effectively visualized from the outside of the catheter main body 121 through the first region 261, and when the catheter 12 is inserted into a living body A, the position of the tip portion 20 of the catheter 12, including the second region 262, can be effectively confirmed by a radioscopic image.

[0056] As shown in Fig. 1, the catheter assembly 10 includes a flexible catheter body 121, a catheter hub 122 connected to the proximal end of the catheter body 121, an inner needle 141 inserted through the catheter body 121, and the needle hub 142 connected to the proximal end of the inner needle 141. As shown in Fig. 3, the distal end portion 20 of the catheter body 121 includes a first region 261 and a second region 262 formed of a material harder than the first region 261 and functioning as a reinforcing layer. The lumen axis C1 (central axis) of the lumen 16 of the catheter body 121 is radially eccentric with respect to the catheter axis C2 (central axis) of the catheter body 121, and includes a thinnest portion 241 where the radial thickness of the peripheral wall portion 18 of the catheter body 121 is smallest. The second region 262 is provided in at least the thinnest portion 241.

[0057] According to this configuration, by providing a relatively thin portion (thinnest portion 241) in the tip portion 20 of the catheter main body 121, it is possible to control the direction in which the catheter main body 121 collapses (the position that serves as the base point for elastic deformation) due to the negative pressure generated when the catheter 12 is suctioned. Therefore, by providing the second region 262 in the thinnest portion 241, it is possible to maintain the flexibility of the catheter main body 121, while the second region 262 effectively suppresses the collapse of the tip portion 20 of the catheter main body 121 when suctioned. This makes it possible to realize a catheter assembly 10 that is easy to use.

[0058] As shown in FIG. 7 , the catheter 12A according to the first modification includes a second region 262A in the catheter body 121. The second region 262A is provided in the thinnest portion 241 of the catheter body 121. In a cross section of the catheter body 121, the second region 262A extends in a direction substantially perpendicular to an imaginary line D that passes through the catheter axis C2 and the lumen axis C1 and is perpendicular to the axis of the catheter body 121. The thickness of the second region 262A gradually decreases in a direction away from the thinnest portion 241 (imaginary line D). Note that the second region 262A is not limited to a case in which the thickness gradually decreases in a direction away from the thinnest portion 241. For example, the thickness of the second region 262A may be constant in a direction away from the thinnest portion 241.

[0059] The first modified example has the following effects.

[0060] The second region 262A can further increase the strength of the catheter body 121 in the vicinity of the thinnest part 241.

[0061] As shown in FIG. 8 , a catheter 12B according to a second modification includes a second region 262B provided in the catheter body 121. In a cross section of the catheter body 121, the second region 262B is provided discontinuously in the circumferential direction of the catheter body 121. The second region 262B includes a plurality of reinforcing portions 50B. The reinforcing portions 50B are spaced apart from one another in the circumferential direction of the catheter body 121 and arranged in parallel in a generally arc-like shape. In a cross section of the catheter body 121, the reinforcing portions 50B are preferably arranged symmetrically with respect to an imaginary line D perpendicular to the axis of the catheter body 121. When the number of reinforcing portions 50B is odd, at least one reinforcing portion 50B is arranged on the imaginary line D. FIG. 8 illustrates a case in which the second region 262B is composed of five reinforcing portions 50B. In a cross section of the catheter body 121, the cross-sectional shape of each reinforcing portion 50B is circular. The cross-sectional shape of each reinforcing portion 50B is not limited to a circular shape. For example, the cross-sectional shape of each reinforcing portion 50B may be rectangular or polygonal.

[0062] It should be noted that the second region 262B is not limited to being composed of five reinforcing portions 50B. For example, the second region 262B may be composed of four or fewer reinforcing portions 50B, or six or more reinforcing portions 50B. Furthermore, the multiple reinforcing portions 50B are not limited to being spaced apart from one another. For example, the multiple reinforcing portions 50B may be in contact with one another in the circumferential direction of the catheter body 121. The multiple reinforcing portions 50B may be connected to one another in the circumferential direction of the catheter body 121.

[0063] The second modified example has the following effects.

[0064] The second region 262B is formed from a plurality of reinforcing portions 50B arranged in parallel and spaced apart in the circumferential direction of the catheter body 121, and by appropriately changing the number and arrangement of the reinforcing portions 50B, the strength of the second region 262B can be effectively adjusted, and therefore the strength of the thinnest portion 241 of the catheter body 121 can be effectively adjusted.

[0065] As shown in FIG. 9 , a catheter 12C according to a third modification includes a second region 262C provided in the catheter body 121. The second region 262C includes multiple reinforcing portions 50C. The multiple reinforcing portions 50C are spaced apart from one another in the radial direction of the catheter body 121. Here, a case will be described in which two reinforcing portions 50C (hereinafter referred to as a first reinforcing portion 501 and a second reinforcing portion 502) are provided, and the second reinforcing portion 502 is provided radially outward of the first reinforcing portion 501. Note that the second region 262 is not limited to being composed of two layers, the first reinforcing portion 501 and the second reinforcing portion 502. For example, a structure in which three or more reinforcing portions 50C are arranged radially of the catheter body 121 is also possible.

[0066] The first reinforcing section 501 is provided on the peripheral wall section 18 of the catheter body 121. The first reinforcing section 501 has the same configuration as the second region 262 of the first embodiment, and therefore a detailed description thereof will be omitted.

[0067] The second reinforcing section 502 is formed, for example, from a radiopaque contrast material. The first reinforcing section 501 and the second reinforcing section 502 are formed in the axial direction of the catheter body 121 by extrusion molding together with the catheter body 121. When extrusion molding the catheter body 121, it is preferable that the number of reinforcing sections 50B is an even number.

[0068] The third modified example has the following effects.

[0069] The second region 262C includes a plurality of reinforcing portions 50C spaced apart from one another in the radial direction of the catheter body 121. By configuring the second region 262C from a plurality of reinforcing portions 50C and appropriately changing the number and arrangement of the reinforcing portions 50C, the strength of the second region 262C can be effectively adjusted.

[0070] The present disclosure is not limited to the above disclosure, and various configurations may be adopted without departing from the gist of the present disclosure.

Claims

1. A hollow cylindrical catheter equipped with a flexible catheter body, the catheter body having a tip portion with a tip opening formed therein, the central axis of the lumen of the catheter body being eccentric with respect to the central axis of the catheter body, the tip portion of the catheter body having: a first region; and a second region formed of a material harder than the first region and functioning as a reinforcing layer, the catheter body further having a thinnest part, where the radial thickness of the peripheral wall of the catheter body is smallest, located adjacent to the lumen in the eccentric direction of the lumen relative to the catheter body, the second region being provided in at least the thinnest part.

2. A catheter according to claim 1, wherein, in a cross section perpendicular to the axial direction of the catheter body, the second region is disposed along the lumen of the catheter body.

3. A catheter according to claim 1 or 2, wherein the first region is formed to be transparent or translucent, and the second region is formed from a radiopaque contrast material.

4. A catheter according to claim 1 or 2, wherein the second region comprises a plurality of reinforcing portions spaced apart from one another along the circumferential direction of the catheter body.

5. A catheter assembly comprising: a flexible, hollow, cylindrical catheter body; a catheter hub connected to the base end of the catheter body and to which a suction device can be connected; an inner needle inserted into the catheter body; and a needle hub connected to the base end of the inner needle, wherein the catheter body has a tip end portion with a tip opening formed therein, the central axis of the lumen of the catheter body is eccentric with respect to the central axis of the catheter body, the tip end portion of the catheter body has: a first region; and a second region formed of a material harder than the first region and functioning as a reinforcing layer, the catheter body further having a thinnest part where the radial thickness of the peripheral wall of the catheter body is smallest, located adjacent to the lumen in the eccentric direction of the lumen relative to the catheter body, and the second region is provided in at least the thinnest part.

6. A catheter assembly according to claim 5, wherein, in a cross section perpendicular to the axial direction of the catheter body, the second region is disposed along the lumen of the catheter body.

7. A catheter assembly according to claim 5 or 6, wherein the first region is formed to be transparent or semi-transparent, and the second region is formed from a radiopaque contrast material.

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