Catheter

Abstract

This catheter 100 comprises: a body 10 that has an inner layer body 11 having a first lumen 31 extending in the axial direction of the catheter 100 and an outer layer body 12 provided on the outer circumference of the inner layer body 11; and a distal-end tip 20 that has a second lumen 32 communicating with the first lumen 31 and is connected to the distal end 10a of the body 10, the distal-end tip 20 having a first portion 21 covering the outer circumferential surface 11p of the inner layer body 11 and a second portion 22 covering at least part of the inner circumferential surface 11q of the inner layer body 11. The catheter configured in this manner is suitable for improving the bondability between the inner layer body and the distal-end tip.

Description

Catheter

[0001] The present disclosure relates to a catheter.

[0002] Known catheters include a main body portion having an inner layer body with an axially extending inner cavity and an outer layer body covering the outer circumference of the inner layer body. A tip chip is connected to the tip side of the main body portion (for example, Patent Document 1). Generally, the inner layer body is made of a material with a low coefficient of friction, such as polytetrafluoroethylene (PTFE), in order to improve the lubricity with external devices such as guide wires inserted into the inner cavity. Generally, the tip chip is made of a highly flexible material such as resin to suppress damage to body cavities such as blood vessels into which the catheter is inserted.

[0003] Japanese Patent Application Laid-Open No. 2019-37572

[0004] In known catheters, since the material constituting the inner layer body and the material constituting the tip chip are different, there is a limit to the bonding property of the interface between the inner layer body and the tip chip. Therefore, when forces such as bending and tension are applied to the catheter, the inner layer body may peel off from the tip chip.

[0005] The present disclosure has been made in view of the above circumstances, and provides a catheter suitable for improving the bonding property between the inner layer body and the tip chip.

[0006] The present disclosure provides a catheter including a main body having an inner layer body with a first inner cavity and an outer layer body provided on the outer circumference of the inner layer body, and a tip chip connected to the tip of the main body, the tip chip having a first portion covering the outer circumferential surface of the inner layer body and a second portion covering at least a part of the inner circumferential surface of the inner layer body.

[0007] It is a cross-sectional view showing an example of the structure of a catheter according to an embodiment of the present disclosure. It is an example of an enlarged view of part II in FIG. 1. Another example of an enlarged view of part II in FIG. 1. Still another example of an enlarged view of part II in FIG. 1. It is an example of a cross-sectional view taken along line III-III in FIG. 1. Another example of a cross-sectional view taken along line III-III in FIG. 1.

[0008] The embodiments of this disclosure will be described below with reference to the drawings. This disclosure is not limited to the embodiments described below, and the embodiments described are merely examples to illustrate the technical features of this disclosure. The shapes and dimensions shown in each drawing are shown only to facilitate understanding of the contents of this disclosure and do not accurately reflect the actual shapes and dimensions.

[0009] In this specification, "tip side" means the direction along the axial direction of the catheter, in which the catheter advances toward the target site. "Proximal side" means the direction along the axial direction of the catheter, in the opposite direction to the tip side. "Tip" refers to the tip end of any member or part, and "proximal end" refers to the proximal end of any member or part.

[0010] [Catheter] Figure 1 is an overall cross-sectional view showing an example of the structure of a catheter 100 according to one embodiment of the present disclosure. The catheter 100 comprises a body 10 and a tip 20 connected to the tip 10a of the body 10. The body 10 has an inner layer 11 having a first lumen 31 extending in the axial direction of the catheter 100 and an outer layer 12 provided on the outer circumference of the inner layer 11. The tip 20 has a second lumen 32 that communicates with the first lumen 31. In this specification, the axial direction of the catheter 100 is the direction along the central axis X of the catheter 100.

[0011] In this embodiment, the tip 20 has a first portion 21 that covers the outer peripheral surface 11p of the inner layer body 11 and a second portion 22 that covers at least a part of the inner peripheral surface 11q of the inner layer body 11.

[0012] As mentioned above, in known catheters, the materials constituting the inner layer and the materials constituting the tip are different. Therefore, there are limitations to the bonding strength at the interface between the inner layer and the tip. When forces such as bending or tension are applied to the catheter, the inner layer may detach from the tip.

[0013] As shown in Figure 1, in the catheter 100 of this embodiment, at least a portion of the inner circumferential surface 11q of the inner layer 11 is covered by the second portion 22 of the inner layer 11. Therefore, the inner layer 11 is less likely to peel off from the tip 20. The catheter 100 of this embodiment is suitable for improving the adhesion between the inner layer 11 and the tip 20.

[0014] Figure 2 is an example of an enlarged view of part II of Figure 1. Figure 3 is another example of an enlarged view of part II of Figure 1. As shown in Figures 2 and 3, the inner layer 11 has an extension 111 that extends toward the tip tip 20 beyond the boundary 51 between the outer layer 12 and the tip tip 20. The first portion 21 of the tip tip 20 covers the outer peripheral surface 111p of the extension 111, and the second portion 22 may cover at least a part of the inner peripheral surface 111q of the extension 111. With this configuration, the bonding between the inner layer 11 and the tip tip 20 can be further improved.

[0015] The length of the second portion 22 of the tip 20 along the axial direction is not necessarily constant in the circumferential direction of the tip 20. Depending on how the cross-section along the axial direction of the catheter 100 is taken, the position of the proximal end 22b of the second portion 22 may differ. For example, if the shape of the end 22b of the second portion 22 is not a straight line along the circumferential direction of the tip 20, but an uneven shape along the circumferential direction of the tip 20, then the length of the second portion 22 will alternate between long and short portions along the circumferential direction of the tip 20. If the shape of the end 22b of the second portion 22 is an uneven shape, the position of the proximal end 22b of the second portion 22 will differ depending on how the cross-section is taken.

[0016] The maximum length L22 of the second portion 22 of the tip tip 20 along the axial direction may be equal to or less than the length L111 of the extension portion 111 along the axial direction. With this configuration, it is possible to improve the bonding between the inner layer 11 and the tip tip 20 while maintaining the lubricity of the inner layer 11. In the example of Figure 2, the maximum length L22 of the second portion 22 of the tip tip 20 along the axial direction is equal to the length L111 of the extension portion 111 along the axial direction. In the example of Figure 3, the maximum length L22 of the second portion 22 of the tip tip 20 along the axial direction is less than the length L111 of the extension portion 111 along the axial direction.

[0017] As described above, the length of the second portion 22 of the tip 20 along the axial direction is not necessarily constant. In this specification, the maximum length L22 of the second portion 22 of the tip 20 along the axial direction means the maximum length of the second portion 22 along the axial direction from the tip end 22a to the base end 22b.

[0018] Figure 4 is yet another example of an enlarged view of part II of Figure 1. As shown in Figure 4, the maximum length L22 along the axial direction of the second part 22 of the tip 20 may be greater than the length L111 along the axial direction of the extension 111. With this configuration, the bonding between the inner layer 11 and the tip 20 can be further improved.

[0019] The maximum length L22 of the second portion 22 of the tip 20 along the axial direction is not particularly limited. The maximum length L22 can be appropriately set by the length of the tip 20 along the axial direction, etc. The maximum length L22 may be in the range of 2 mm or more and 5 mm or less. The maximum length L22 may also be 2 mm or more and 4 mm or less, or 2 mm or more and 3 mm or less. When the maximum length L22 is within the above numerical range, sufficient bonding between the inner layer 11 and the tip 20 can be ensured.

[0020] As shown in Figures 2 to 4, the thickness of the second portion 22 of the tip 20 of the catheter 100 may decrease from the tip side towards the proximal end side. With this configuration, the proximal end 22b of the second portion and the inner circumferential surface 11q of the inner layer body 11 are more likely to be flush. That is, the first lumen 31 and the second lumen 32 can be smoothly connected. Therefore, the lubricity of the lumen of the catheter 100 can be improved.

[0021] The maximum thickness T22 of the second portion 22 of the tip 20 may be, for example, in the range of 10 μm to 100 μm. When the maximum thickness T22 is within the above numerical range, the second portion 22 is less likely to peel off from the extended portion 111 of the inner layer 11. The maximum thickness T22 may be 10 μm to 90 μm, 10 μm to 80 μm, 10 μm to 70 μm, 10 μm to 60 μm, or even 10 μm to 50 μm.

[0022] As described above, the thickness of the second portion 22 of the tip 20 may decrease from the tip end to the proximal end of the catheter 100. In this specification, the maximum thickness T22 of the second portion 22 of the tip 20 means the maximum thickness of the second portion 22 of the tip 20 in a cross-section along the axial direction of the catheter 100.

[0023] The maximum thickness T21 of the first portion 21 of the tip 20 can be, for example, in the range of 30 μm to 290 μm. When the maximum thickness T21 is within the above numerical range, the rigidity of the tip 20 is easily maintained. The maximum thickness T21 may also be 60 μm to 250 μm, 220 μm to 290 μm, or even 30 μm to 140 μm.

[0024] In this specification, the maximum thickness T21 of the first portion 21 of the tip 20 means the maximum thickness of the first portion 21 of the tip 20 in a cross-section along the axial direction of the catheter 100.

[0025] The tip 20 has a tapered shape in which the outer diameter at the tip is smaller than the outer diameter at the proximal end. As shown in Figure 1, the inner diameter of the tip 20 may increase from the tip to the proximal end of the catheter 100. In other words, the second lumen 32 may have a tapered shape in which the inner diameter at the tip is smaller than the inner diameter at the proximal end. With such a configuration, it is possible to improve the bonding between the inner layer body 11 and the tip 20 while maintaining the rigidity of the tip 20. A structure in which the inner diameter of the tip 20 increases from the tip to the proximal end can be realized, for example, when the thickness of the second portion 22 of the tip 20 decreases from the tip to the proximal end of the catheter 100.

[0026] Figure 5 is an example of a cross-sectional view taken along line III-III in Figure 1. As shown in Figure 5, the first portion 21 of the tip 20 covers the entire outer surface 11p of the inner layer 11. More specifically, the first portion 21 of the tip 20 covers the entire outer surface 111p of the extension 111.

[0027] As shown in Figure 5, when observing the cross-section of the tip 20 along the radial direction perpendicular to the axial direction, the second portion 22 of the tip 20 may cover the entire inner circumferential surface 11q of the inner layer body 11. More specifically, the second portion 22 may cover the entire inner circumferential surface 111q of the extension portion 111. However, the above cross-section is assumed to pass through the first portion 21, the inner layer body 11 (extension portion 111), and the second portion 22. In other words, the second portion 22 may exist along the entire inner circumferential surface 11q of the inner layer body 11. With such a configuration, the exposed area of ​​the inner circumferential surface 11q of the inner layer body 11 in the second lumen 32 can be reduced. This can further improve the bonding between the inner layer body 11 and the tip 20.

[0028] Figure 6 is another example of the III-III cross-sectional view in Figure 1. As shown in Figure 6, when observing the cross-section of the tip 20 along the radial direction perpendicular to the axial direction, the portion Y22 where the second portion 22 exists and the portion N22 where the second portion 22 does not exist may be alternately provided along the inner circumferential surface 11q of the inner layer body 11. However, the above cross-section is assumed to pass through the first portion 21, the inner layer body 11 (extension portion 111), and the second portion 22. Even with such a configuration, the contact area between the tip 20 and the inner layer body 11 can be increased. This improves the bonding between the inner layer body 11 and the tip 20.

[0029] In the example shown in Figure 6, the inner circumferential surface 11q of the inner layer body 11 is exposed in the portion N22 where the second portion 22 is absent. Such a structure can be realized, for example, when the shape of the end portion 22b of the second portion 22 is not a straight line along the circumferential direction of the tip 20, but rather an uneven shape along the circumferential direction of the tip 20.

[0030] The number of portions Y22 and N22 is not particularly limited. As shown in Figure 6, four portions Y22 and four portions N22 may be alternately provided along the inner circumferential surface 11q of the inner layer body 11.

[0031] The sections Y22 and N22 may be provided at equal intervals. With this configuration, the peeling of the inner layer 11 from the tip 20 can be suppressed in a balanced manner.

[0032] The circumferential lengths of portion Y22 and portion N22 may be the same or different.

[0033] The inner circumferential surface 11q of the inner layer body 11 may have a plurality of grooves formed along the axial direction. A portion Y22 may be arranged in each of the plurality of grooves. With such a configuration, it is possible to suppress the peeling of the inner layer body 11 from the tip 20 while maintaining the lubricity of the second lumen 32.

[0034] The inner layer 11 may be made of a material with a low coefficient of friction. Such a configuration can improve lubrication with external devices such as guidewires inserted into the lumen of the catheter 100, particularly the first lumen 31. A material with a low coefficient of friction is typically polytetrafluoroethylene (PTFE). The inner layer 11 may be made of PTFE.

[0035] The outer layer 12 may be made of a resin material. The resin material is not particularly limited. For example, polyamide, polyamide elastomer, polyester, polyurethane, etc. can be used as the resin material.

[0036] The tip 20 may be made of a resin material. Since the viscosity of the resin material decreases when heated, a tip 20 having a first portion 21 that covers the outer peripheral surface 11p of the inner layer body 11 and a second portion 22 that covers at least a part of the inner peripheral surface 11q of the inner layer body 11 can be easily manufactured.

[0037] As shown in Figure 1, the main body 10 may further have a reinforcing member 13 positioned between the inner layer 11 and the outer layer 12. This configuration can improve the strength of the main body 10.

[0038] The reinforcing body 13 may be wound around the outer circumference of the inner layer body 11. The reinforcing body 13 may be a coil body made of a metallic material. The coil body is formed by tightly winding individual wires, and is typically a single coil in which one individual wire is tightly wound. The coil body may also be a multi-coil in which multiple individual wires are arranged to form a strip, and this strip is tightly wound. The individual wires constituting the coil body may be solid wires, or they may be stranded wires having a structure in which multiple stranded wires are twisted together.

[0039] [Method for Manufacturing a Catheter] The catheter 100 of this embodiment can be manufactured, for example, by the following method.

[0040] First, a core wire is prepared, having a tapered section at the tip and a straight section located further back from the tapered section. The tapered section is the part whose outer diameter decreases towards the tip. The straight section is the part whose outer diameter remains constant along the long axis of the core wire. The outer circumference of the core wire is coated with PTFE to form an inner layer 11. Next, a coil body is wound around the outer circumference of the inner layer 11 to form a reinforcing body 13. Next, a resin material such as polyamide is coated around the outer circumference of the reinforcing body 13 to form an outer layer 12. At this time, the reinforcing body 13 and the outer layer 12 are formed such that the inner layer 11 has an extended portion 111 that extends towards the tip beyond the boundary portion 51. Of the inner layer 11, the extended portion 111 is provided on the outer circumference of the tapered section of the core wire, and the portion other than the extended portion 111 is provided on the outer circumference of the straight section of the core wire. This gives rise to the main body 10.

[0041] Next, a cylindrical resin material is placed on the outer circumference of the extension portion 111. The resin material is heated to join the base end of the resin material with the tip of the main body 10, forming the tip 20. At this time, a gap exists between the inner circumferential surface 111q of the extension portion 111 and the outer circumferential surface of the tapered portion of the core wire. The thickness of the gap decreases from the tip side towards the base end side. When the heating treatment is performed in this state, a portion of the molten tip 20 flows into the gap. This forms a second portion 22 that covers at least a part of the inner circumferential surface 11q of the inner layer body 11.

[0042] After cooling, the core wire is withdrawn to obtain the catheter 100.

[0043] This disclosure provides a catheter comprising a main body having an inner layer having a first lumen and an outer layer provided on the outer circumference of the inner layer, and a tip connected to the tip of the main body having a second lumen communicating with the first lumen, the tip having a first portion covering the outer surface of the inner layer and a second portion covering at least a part of the inner surface of the inner layer (Disclosure 1).

[0044] According to such disclosure (Disclosure 1), at least a part of the inner peripheral surface of the inner layer body is covered by the second part of the inner layer body. The tip chip sandwiches the tip part of the inner layer body, and the contact area between the tip chip and the inner layer body becomes large. Therefore, it is difficult for the inner layer body to peel off from the tip chip. The catheter of Disclosure 1 is suitable for improving the bonding property between the inner layer body and the tip chip.

[0045] In the above disclosure (Disclosure 1), the second part may cover the entire inner peripheral surface of the inner layer body (Disclosure 2).

[0046] According to such disclosure (Disclosure 2), the bonding property between the inner layer body and the tip chip can be further improved.

[0047] In the above disclosure (Disclosures 1 and 2), the inner layer body has an extension part that extends to the tip chip side rather than the boundary part between the outer layer body and the tip chip, the first part covers the outer peripheral surface of the extension part, and the second part may cover at least a part of the inner peripheral surface of the extension part (Disclosure 3).

[0048] According to such disclosure (Disclosure 3), the bonding property between the inner layer body and the tip chip can be further improved.

[0049] In the above disclosure (Disclosure 3), the maximum length of the second part along the axial direction may be equal to or smaller than the length of the extension part along the axial direction (Disclosure 4).

[0050] According to such disclosure (Disclosure 4), the bonding property between the inner layer body and the tip chip can be improved while maintaining the lubricity of the inner layer body.

[0051] In the above disclosure (Disclosure 3), the maximum length of the second part along the axial direction may be larger than the length of the extension part along the axial direction (Disclosure 5).

[0052] According to such disclosure (Disclosure 5), the bonding property between the inner layer body and the tip chip can be further improved.

[0053] In the above disclosure (Disclosures 1 - 5), the maximum length of the second part along the axial direction may be in the range of 2 mm or more and 5 mm or less (Disclosure 6).

[0054] According to such disclosure (Disclosure 6), sufficient bonding between the inner layer and the tip can be ensured.

[0055] In the above disclosure (Disclosure 1-6), the thickness of the second portion may decrease from the tip end to the proximal end of the catheter (Disclosure 7).

[0056] According to such disclosure (Disclosure 7), the lubricity of the catheter lumen can be improved.

[0057] In the above disclosure (Disclosure 1-7), the maximum thickness of the second portion may be in the range of 10 μm or more and 100 μm or less (Disclosure 8).

[0058] According to such disclosure (Disclosure 8), the second portion is less likely to peel off from the extended portion of the inner layer.

[0059] In the above disclosure (Disclosure 1-8), the inner diameter of the tip of the catheter may increase from the tip side toward the proximal end (Disclosure 9).

[0060] According to such disclosure (Disclosure 9), it is possible to improve the bonding between the inner layer and the tip while maintaining the rigidity of the tip.

[0061] In the above disclosure (Disclosure 1-9), portions where the second portion is present and portions where the second portion is not present may be alternately provided along the inner circumferential surface of the inner layer (Disclosure 10).

[0062] According to such disclosure (Disclosure 10), the bonding between the inner layer and the tip can be improved.

[0063] In the above disclosure (Disclosure 1-10), the main body may further include a reinforcing member disposed between the inner layer and the outer layer (Disclosure 11).

[0064] According to such disclosure (Disclosure 11), the strength of the main body can be improved.

[0065] In the above disclosure (Disclosure 1-11), the tip may be made of a resin material (Disclosure 12).

[0066] According to such disclosure (Disclosure 12), an end tip having a first portion that covers the outer circumferential surface of the inner layer and a second portion that covers at least a part of the inner circumferential surface of the inner layer can be easily manufactured.

[0067] The catheter relating to this disclosure has been described above with reference to the drawings. However, this disclosure is not limited to the above embodiments, and various modifications are possible.

Claims

1. A catheter (100) comprising: a main body (10) having an inner layer (11) having a first lumen (31) and an outer layer (12) provided on the outer circumference of the inner layer (11); and a tip (20) having a second lumen (32) communicating with the first lumen (31) and connected to the tip (10a) of the main body (10), the tip (20) having a first portion (21) covering the outer circumferential surface (11p) of the inner layer (11) and a second portion (22) covering at least a part of the inner circumferential surface (11q) of the inner layer (11).

2. The catheter (100) according to claim 1, wherein the second portion (22) covers the entire inner circumferential surface (11q) of the inner layer (11).

3. The catheter (100) according to claim 1, wherein the inner layer (11) has an extension (111) that extends toward the tip tip (20) beyond the boundary (51) between the outer layer (12) and the tip tip (20), the first portion (21) covers the outer peripheral surface (111p) of the extension (111), and the second portion (22) covers at least a portion of the inner peripheral surface (111q) of the extension (111).

4. The catheter (100) according to claim 3, wherein the maximum length (L22) of the second portion (22) along the axial direction is equal to or less than the length (L111) of the extension portion (111) along the axial direction.

5. The catheter (100) according to claim 3, wherein the maximum length (L22) of the second portion (22) along the axial direction is greater than the length (L111) of the extension portion (111) along the axial direction.

6. The catheter (100) according to any one of claims 1 to 5, wherein the maximum length (L22) of the second portion (22) along the axial direction is in the range of 2 mm or more and 5 mm or less.

7. The catheter (100) according to any one of claims 1 to 6, wherein the thickness of the second portion (22) decreases from the tip end to the proximal end of the catheter (100).

8. The catheter (100) according to any one of claims 1 to 7, wherein the maximum thickness (T22) of the second portion (22) is in the range of 10 μm or more and 100 μm or less.

9. The catheter (100) according to any one of claims 1 to 8, wherein the inner diameter of the tip (20) increases from the tip side to the proximal side of the catheter (100).

10. The catheter (100) according to any one of claims 1 to 9, wherein along the inner circumferential surface (11q) of the inner layer body (11), portions (Y22) in which the second portion (22) is present and portions (N22) in which the second portion (22) is absent are alternately provided.

11. The catheter (100) according to any one of claims 1 to 10, wherein the main body (10) further comprises a reinforcing member (13) disposed between the inner layer (11) and the outer layer (12).

12. The catheter (100) according to any one of claims 1 to 11, wherein the tip (20) is made of a resin material.

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