Catheter

Abstract

Provided is a catheter wherein, for example, when the same is used together with an outer catheter, a liquid can be made to flow through a lumen of the outer catheter without removing the catheter of the present disclosure.　This catheter 1 comprises a shaft 11, wherein the shaft 11 includes a large diameter section 11B, a proximal end-side small diameter section 11C that is positioned on the proximal end side of the large diameter section 11B and has a smaller outer diameter than the outer diameter of the large diameter section 11B, a first lumen L11 that penetrates through the shaft 11 along the length direction from the distal end to the proximal end, and a second lumen L21 that penetrates through the large diameter section 11B along the length direction and has a distal end opening L21a and a proximal end opening L21b.

Description

catheter

[0001] The present disclosure relates to catheters.

[0002] For example, a known procedure involves inserting a microcatheter along a guidewire, and then guiding another catheter with a larger inner diameter (hereinafter also referred to as an "outer catheter") along the microcatheter to a predetermined location within a blood vessel.

[0003] In such procedures, a microcatheter is inserted into the lumen of an outer catheter. Therefore, if there is a large clearance between the outer peripheral surface of the microcatheter and the inner peripheral surface of the outer catheter, a large step occurs at the tip of the outer catheter. Due to this large step, the tip of the outer catheter may get caught on a branching part of the blood vessel when the outer catheter is pushed along the microcatheter through the blood vessel.

[0004] To prevent such snagging, an improved catheter with a larger outer diameter has been proposed as an alternative to the above-mentioned microcatheter (see, for example, Patent Document 1). The improved catheter is formed so that the outer diameter of the portion near the tip that is inserted into the lumen of the outer catheter is larger than that of a conventional microcatheter, so that the clearance with the outer catheter is reduced.

[0005] Japanese Patent Application Laid-Open No. 2022-133795

[0006] When injecting a liquid such as a contrast agent using the conventional technique described above, it is necessary to withdraw the guidewire and then allow the liquid to flow through the guidewire lumen of the improved catheter, or to withdraw the improved catheter and then allow the liquid to flow through the lumen of the outer catheter. However, such a technique is cumbersome and may reduce the speed of the procedure.

[0007] The present specification discloses a catheter that, for example, when used in conjunction with an outer catheter, allows fluid to flow through the lumen of the outer catheter without withdrawing the improved catheter.

[0008] The catheter of the present disclosure includes: (1) a shaft, the shaft including a large-diameter section; a proximal-side small-diameter section disposed proximal to the large-diameter section and having an outer diameter smaller than that of the large-diameter section; a first lumen extending longitudinally through the shaft from its distal end to its proximal end; and a second lumen having a distal opening and a proximal opening and extending longitudinally through the large-diameter section. With this configuration, for example, when using an outer catheter in combination, it is possible to flow a liquid into the lumen of the outer catheter (e.g., to deliver a contrast agent or aspirate a body fluid) without removing the catheter of the present disclosure. As a result, procedures can be performed quickly. In addition, because the shaft includes a proximal-side small-diameter section, the flow path of the liquid in the lumen of the outer catheter is widened. As a result, pressure loss of the liquid flowing through the lumen of the outer catheter can be reduced, ensuring reliable angiography, aspirating body fluids, and the like.

[0009] (2) In the catheter described in (1), the shaft may include a distal small diameter portion disposed distally of the large diameter portion and having an outer diameter smaller than that of the large diameter portion. With this configuration, the distal small diameter portion can be advanced within the blood vessel leading the large diameter portion, and the catheter can be smoothly delivered to the site for treatment, such as angiography.

[0010] (3) In the catheter described in (2), the distal small diameter section may have a distal tapered section whose diameter decreases from the tip of the large diameter section toward the distal side, and the distal opening of the second lumen may be provided on the outer peripheral surface of the distal tapered section. This configuration allows the catheter to move forward smoothly and suppresses bending stress concentration at the base end of the distal small diameter section, thereby preventing plastic deformation and breakage of the shaft.

[0011] (4) In the catheters of (1) to (3), the proximal small diameter section may have a proximal tapered section whose diameter decreases from the proximal end of the large diameter section toward the proximal side, and the proximal opening of the second lumen may be provided on the outer peripheral surface of the proximal tapered section. This configuration can suppress concentration of bending stress at the tip of the proximal small diameter section, thereby preventing plastic deformation and breakage of the shaft.

[0012] As used herein, "distal side" refers to the direction along the longitudinal axis of the shaft (also referred to as "longitudinal direction"), in which the catheter advances toward the treatment site (distal side). "Proximal side" refers to the longitudinal direction, in the direction opposite to the distal side (proximal side). "Distal" refers to the distal end of any component. "Distal" refers to the distal end of any component. "Proximal end" refers to the proximal end of any component. "Proximal end" refers to the proximal end of any component. "Radial direction" refers to the direction perpendicular to the longitudinal axis of the shaft.

[0013] Fig. 1 is a schematic cross-sectional view showing a first embodiment; Fig. 2 is a schematic cross-sectional view showing an enlarged portion of Fig. 1; Fig. 3 is a schematic left side view of Fig. 1; Fig. 4 is a schematic cross-sectional view illustrating a state in which the first embodiment is used; Fig. 5 is a schematic cross-sectional view showing an enlarged portion of a second embodiment;

[0014] The catheter of the present disclosure comprises a shaft, the shaft including a large diameter portion, a proximal small diameter portion disposed on the proximal side of the large diameter portion and having an outer diameter smaller than the outer diameter of the large diameter portion, a first lumen passing through the shaft longitudinally from the tip to the base end, and a second lumen having a tip opening and a base opening and passing through the large diameter portion longitudinally.

[0015] Hereinafter, first and second embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the embodiments shown in the drawings. The dimensions of each part shown in the drawings are shown to facilitate understanding of the implementation content and do not necessarily correspond to the actual dimensions.

[0016] In Figures 1, 2, 4, and 5, the left side of the figure is the tip side (distal side) that is inserted deeper into the body, and the right side is the base side (proximal side, hand side) that is operated by a technician such as a doctor.

[0017] [First embodiment] Fig. 1 is a schematic cross-sectional view showing a first embodiment. Fig. 2 is a schematic cross-sectional view showing an enlarged portion of Fig. 1. Fig. 3 is a schematic left side view of Fig. 1. As shown in Figs. 1 to 3, a catheter 1 has, for example, a shaft 11 and a gripping member 21.

[0018] The shaft 11 is an elongated member and includes a large diameter portion 11B, a proximal small diameter portion 11C, a first lumen L11, and a second lumen L21.

[0019] The large diameter portion 11B is the portion with the largest outer diameter in the longitudinal direction. The large diameter portion 11B may be formed, for example, in a substantially cylindrical shape with a constant outer diameter and a predetermined length along the longitudinal direction of the shaft 11.

[0020] The proximal small diameter portion 11C is disposed on the proximal side of the large diameter portion 11B and has an outer diameter smaller than that of the large diameter portion 11B. The shape of the proximal small diameter portion 11C is not particularly limited. For example, the proximal small diameter portion 11C may have a constant outer diameter along the longitudinal axis direction. The proximal small diameter portion 11C may have two or more portions with different outer diameters. In such a case, the proximal small diameter portion 11C may be formed by connecting two or more cylindrical portions (straight portions) with different outer diameters. The proximal small diameter portion 11C may include a tapered portion. The proximal small diameter portion 11C may include a straight portion and a tapered portion.

[0021] In this embodiment, the proximal small diameter section 11C has a proximal tapered section 11C1 that tapers from the proximal end of the large diameter section 11B toward the proximal end. Specifically, the proximal tapered section 11C1 is continuous with the proximal end of the large diameter section 11B and gradually tapers toward the proximal end. This allows the outer catheter (described later) to be easily delivered until its tip reaches the outer peripheral surface of the large diameter section 11B, while also suppressing bending stress concentration at the tip of the proximal small diameter section 11C, preventing plastic deformation and breakage of the shaft 11. A straight section 11C2 with a constant outer diameter toward the proximal end is located at the proximal end of the proximal tapered section 11C1.

[0022] The first lumen L11 is a lumen that passes through the shaft 11 in the longitudinal direction from the distal end to the proximal end. The first lumen L11 has a distal opening L11a and a proximal opening L11b. The distal opening L11a is located at the distal end of the first lumen L11 and opens toward the distal end. The proximal opening L11b is located at the proximal end of the first lumen L11 and opens toward the proximal end. For example, a guidewire for guiding the catheter 1 can be inserted through the first lumen L11.

[0023] The second lumen L21 passes through the large diameter portion 11B in the longitudinal direction. The second lumen L21 has a distal opening L21a and a proximal opening L21b. The distal opening L21a is located at the distal end of the second lumen L21 and opens toward the distal side. The proximal opening L21b is located at the proximal end of the second lumen L21 and opens toward the proximal side. Liquids such as contrast agents and body fluids can be passed through the second lumen L21.

[0024] The thickness of the shaft 11 radially outward from the first lumen L11 is thick (thick-walled) at the large diameter section 11B and thin at the proximal small diameter section 11C. The second lumen L21 passes through the thick-walled section in the longitudinal direction. The first lumen L11 does not pass through the thick-walled section in the longitudinal direction. The second lumen L21 does not pass through the shaft 11 from the distal end to the proximal end in the longitudinal direction.

[0025] The central axis C1 of the shaft 11 is located inside the first lumen L11. The central axis C2 of the second lumen L21 is disposed at a position eccentric to the central axis C1 of the shaft 11. The central axis C2 of the second lumen L21 is disposed at a position different from the position of the central axis C1 of the shaft 11.

[0026] In this embodiment, the tip of the large diameter portion 11B is the tip of the shaft 11, and the tip of the shaft 11 is composed of a flat portion 11a formed in a planar shape extending in the radial direction (perpendicular to the long axis of the shaft 11). The distal opening L21a of the second lumen L21 opens toward the distal side on the flat portion 11a. The proximal opening L21b of the second lumen L21 is provided on the outer peripheral surface 11C1a of the proximal tapered portion 11C1.

[0027] The distal opening L21a is located radially inward of the outer peripheral surface of the large diameter portion 11B and radially outward of the outer peripheral surface of the proximal small diameter portion 11C where the outer diameter is smallest. The proximal opening L21b is located radially inward of the outer peripheral surface of the large diameter portion 11B and radially outward of the outer peripheral surface of the proximal small diameter portion 11C where the outer diameter is smallest.

[0028] The material constituting the shaft 11 is preferably antithrombotic, flexible, and biocompatible, since the shaft 11 is inserted into a body cavity. Examples of materials for the shaft 11 include resin materials such as polyamide, polyamide elastomer, polyolefin, polyester, polyester elastomer, polyurethane, silicone, and fluororesin.

[0029] A cylindrical reinforcing body may be provided inside the shaft 11 so as to surround the first lumen L11. Examples of the reinforcing body include a coil body and a cylindrical mesh body. The proximal end of the shaft 11 may be made of a material having higher rigidity than the above-mentioned resin material. Examples of the highly rigid material include a resin material having higher rigidity than the above-mentioned resin material, and metal materials such as stainless steel (e.g., SUS304) and superelastic alloys (e.g., nickel-titanium alloys).

[0030] The gripping member 21 is a member with which the operator grips the catheter 1. The gripping member 21 is connected to the proximal end of the shaft 11. The gripping member 21 has an inner cavity 21h that communicates with the first lumen L11 and an opening 21b formed at the proximal end of the inner cavity 21h. The shape of the gripping member 21 is not particularly limited. For example, the gripping member 21 may be formed in a shape that is easy for the operator to manipulate. The gripping member 21 may be detachably connected to the proximal end of the shaft 11.

[0031] 4 is a schematic cross-sectional view illustrating the first embodiment in use. Referring to FIG. 4, a procedure is illustrated in which a guidewire G and an outer catheter C (e.g., an injection catheter, a suction catheter, or the like) are used together with the catheter 1 to perform intravascular imaging while injecting a contrast agent L through the lumen Ch of the outer catheter C.

[0032] Prior to the catheter 1, a guide wire G is inserted into the blood vessel V and advanced to the imaging region P in advance.

[0033] Next, the catheter 1 is inserted along the guidewire G to the imaging site P. Specifically, after the base end of the guidewire G is inserted into the distal end opening L11a of the shaft 11, the catheter 1 is inserted into the blood vessel V from the distal end of the shaft 11, and the catheter 1 is advanced along the guidewire G to the imaging site P.

[0034] Next, the outer catheter C is inserted along the catheter 1 to the imaging site P. Specifically, after the proximal end of the catheter 1 is inserted into the distal opening of the outer catheter C, the outer catheter C is inserted from its distal end into the blood vessel V and the outer catheter C is advanced along the catheter 1 to just before the imaging site P. Compared to the proximal small diameter portion 11C, the clearance between the outer peripheral surface of the large diameter portion 11B and the inner peripheral surface of the outer catheter C is smaller. Therefore, when the outer catheter C is guided to the imaging site P using the catheter 1 as a guide, no large step is generated at the distal end of the outer catheter C, and the outer catheter C will not get caught on a branching portion of the blood vessel V, for example.

[0035] Next, the catheter 1 is slid in the lumen of the outer catheter C until the distal opening L21a is accurately aligned with the imaging region P. Next, contrast medium L is injected into the lumen of the outer catheter C from its proximal end. The injected contrast medium L flows through the lumen Ch of the outer catheter C, from the proximal opening L21b, into the second lumen L21, and then passes through the second lumen L21 to be released into the blood vessel V from the distal opening L21a (see the arrow in FIG. 4 ). This injects the contrast medium L into the blood vessel near the imaging region P, enabling imaging of the imaging region P. If necessary, after the catheter 1 is withdrawn from the outer catheter C, thrombi and the like within the blood vessel V may be aspirated by the outer catheter C. The catheter 1 and the outer catheter C may be delivered through the lumen of a guiding catheter.

[0036] As described above, the catheter 1 has the above-described configuration, so that, for example, when using the outer catheter C in combination, it is possible to flow a liquid (for example, to deliver a contrast agent or aspirate a body fluid) into the lumen Ch of the outer catheter C without pulling out the catheter 1 and the guidewire G. As a result, the procedure can be performed quickly.

[0037] The catheter 1 is provided with a proximal small-diameter section 11C, which widens the flow path of the liquid in the lumen Ch of the outer catheter C. As a result, pressure loss of the liquid flowing through the lumen Ch of the outer catheter C can be suppressed, and angiography, aspiration of body fluids, and the like can be reliably performed.

[0038] Second Embodiment Figure 5 is a schematic cross-sectional view showing an enlarged portion of the second embodiment. As shown in Figure 5, the catheter 2 includes, for example, a shaft 12 and a gripping member 21 (see Figure 1), not shown. The second embodiment differs from the first embodiment in that the shaft 12 includes a distal small diameter section 12A and a second lumen L22. The configurations of the second embodiment are the same as those of the first embodiment, except for the configurations of the distal small diameter section 12A and the second lumen L22, as described below. The large diameter section 12B and the proximal small diameter section 12C are the same as the large diameter section 11B and the proximal small diameter section 11C of the first embodiment, respectively. The proximal small diameter section 12C has a proximal tapered section 12C1 whose diameter decreases from the proximal end of the large diameter section 12B toward the proximal end. A straight section 12C2, whose outer diameter is constant toward the proximal end, is located at the proximal end of the proximal tapered section 12C1. The first lumen L12 has the same configuration as the first lumen L11 of the first embodiment. The first lumen L12 has a distal opening L12a and a proximal opening (an opening corresponding to the proximal opening L11b in FIG. 1). Detailed description of the same configuration as the first embodiment will be omitted. The manner of use of the catheter 2 is the same as that of the first embodiment.

[0039] The shaft 12 is an elongated member and includes a large diameter portion 12B, a distal small diameter portion 12A, a proximal small diameter portion 12C, a first lumen L12, and a second lumen L22.

[0040] The distal small diameter portion 12A is disposed distally of the large diameter portion 12B and has an outer diameter smaller than that of the large diameter portion 12B. The shape of the distal small diameter portion 12A is not particularly limited. For example, the distal small diameter portion 12A may have a constant outer diameter along the longitudinal axis. The distal small diameter portion 12A may have two or more portions with different outer diameters. In such a case, the distal small diameter portion 12A may be formed by connecting two or more cylindrical portions (straight portions) with different outer diameters. The distal small diameter portion 12A may include a truncated cone-shaped portion (tapered portion) whose outer diameter gradually changes along the longitudinal axis. The distal small diameter portion 12A may include a straight portion and a tapered portion.

[0041] In this embodiment, the distal small diameter section 12A has a distal tapered section 12A1 that tapers from the tip of the large diameter section 12B toward the distal end. Specifically, the distal tapered section 12A1 is continuous with the tip of the large diameter section 12B and gradually tapers toward the distal end. This allows the catheter 2 to move forward smoothly and prevents plastic deformation and breakage of the shaft 12 by suppressing bending stress concentration at the base end of the distal small diameter section 12A. A straight section 12A2 with a constant outer diameter is located at the tip of the distal tapered section 12A1.

[0042] The second lumen L22 passes through the large diameter portion 12B in the longitudinal direction. The second lumen L22 has a distal opening L22a and a proximal opening L22b. In the second lumen L22 of this embodiment, the distal opening L22a is provided in the outer peripheral surface 12A1a of the distal tapered portion 12A1, and the proximal opening L22b is provided in the outer peripheral surface 12C1a of the proximal tapered portion 12C1.

[0043] The thickness of the shaft 12 radially outward from the first lumen L12 is thicker (thicker) at the large diameter section 12B and thinner at the distal small diameter section 12A and the proximal small diameter section 12C. The second lumen L22 passes through the thicker section in the longitudinal direction. The first lumen L12 does not pass through the thicker section in the longitudinal direction. The second lumen L22 does not pass through the shaft 12 from the distal end to the proximal end in the longitudinal direction.

[0044] The central axis C1 of the shaft 12 is located inside the first lumen L12. The central axis C2 of the second lumen L22 is disposed at a position eccentric to the central axis C1 of the shaft 12. The central axis C2 of the second lumen L22 is disposed at a position different from the position of the central axis C1 of the shaft 12.

[0045] The distal opening L22a is located radially inward of the outer peripheral surface of the large diameter portion 12B and radially outward of the outer peripheral surface of the distal small diameter portion 12A where the outer diameter is smallest. The proximal opening L22b is located radially inward of the outer peripheral surface of the large diameter portion 12B and radially outward of the outer peripheral surface of the proximal small diameter portion 12C where the outer diameter is smallest.

[0046] As described above, the catheter 2 has the above-described configuration, so that, for example, when using the outer catheter C in combination, it is possible to flow a liquid into the lumen Ch of the outer catheter C (for example, to deliver a contrast agent or aspirate a body fluid) without pulling out the catheter 2 and the guidewire G. As a result, the procedure can be performed quickly.

[0047] The catheter 2 has a distal small-diameter section 12A, which allows the catheter 2 to be advanced within a blood vessel by leading the large-diameter section 12B, and allows the catheter 2 to be smoothly delivered to the site of treatment, such as angiography.

[0048] The present disclosure is not limited to the configurations of the above-described embodiments, but is intended to include all modifications within the meaning and scope of the claims as defined by the claims. Part of the configurations of the above-described embodiments may be deleted or replaced with other configurations, or other configurations may be added to the configurations of the above-described embodiments.

[0049] For example, in the first embodiment described above, the catheter 1 is described in which the large diameter section 11B, the proximal tapered section 11C1, and the straight section 11C2 are connected in this order toward the proximal end. The proximal small diameter section is not particularly limited as long as it has an outer diameter smaller than the outer diameter of the large diameter section. The proximal small diameter section may be provided with either a tapered section or a straight section alone to achieve the desired effect. The proximal small diameter section may be provided with any combination of tapered sections and straight sections along the longitudinal axis to achieve the desired effect.

[0050] In the second embodiment described above, the catheter 2 is described in which the large diameter section 12B, the distal tapered section 12A1, and the straight section 12A2 are connected in this order toward the distal end. The distal small diameter section is not particularly limited as long as it has an outer diameter smaller than that of the large diameter section. The distal small diameter section may be provided with either a tapered section or a straight section alone to achieve the desired effect. The distal small diameter section may be provided with any combination of tapered sections and straight sections along the longitudinal axis to achieve the desired effect.

[0051] In the illustrated embodiment, the shafts 11 and 12 are formed of a single material (single layer). The shafts may be formed of multiple layers. For example, a liner may be provided on the inner wall of the shaft 11 on the lumen L11 side. A liner may be provided on the inner wall of the shaft 12 on the lumen L12 side. Examples of liner materials include polytetrafluoroethylene (PTFE) and polyetheretherketone (PEEK).

Claims

1. A catheter (1, 2) comprising a shaft (11, 12), the shaft (11, 12) including: a large diameter portion (11B, 12B); a proximal small diameter portion (11C, 12C) disposed proximal to the large diameter portion (11B, 12B) and having an outer diameter smaller than the outer diameter of the large diameter portion (11B, 12B); a first lumen (L11, L12) passing through the shaft (11, 12) along the longitudinal direction from the tip to the base end; and a second lumen (L21, L22) having a tip opening (L21a, L22a) and a base opening (L21b, L22b) and passing through the large diameter portion (11B, 12B) along the longitudinal direction.

2. A catheter (2) as described in claim 1, wherein the shaft (12) includes a distal small diameter portion (12A) disposed distal to the large diameter portion (12B) and having an outer diameter smaller than the outer diameter of the large diameter portion (12B).

3. A catheter (2) as described in claim 2, wherein the distal small diameter section (12A) has a distal tapered section (12A1) that reduces in diameter from the distal end of the large diameter section (12B) toward the distal end, and the distal opening (L22a) of the second lumen (L22) is provided on the outer peripheral surface (12A1a) of the distal tapered section (12A1).

4. A catheter (1, 2) according to any one of claims 1 to 3, wherein the base-side small diameter portion (11C, 12C) has a base-side tapered portion (11C1, 12C1) that reduces in diameter from the base end of the large diameter portion (11B, 12B) toward the base end, and the base-side opening (L21b, L22b) of the second lumen (L21, L22) is provided on the outer peripheral surface (11C1a, 12C1a) of the base-side tapered portion (11C1, 12C1).

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