catheter

Abstract

To improve strength of a tube having a lumen in a catheter.SOLUTION: A catheter includes a first tube having a first lumen and a second tube having a second lumen. The first tube has: an inner layer configuring an innermost layer of the first lumen; an outer layer encircling the inner layer; and a reinforcement layer put between the inner layer and an outer layer.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The technology disclosed herein relates to catheters. [Background technology]

[0002] A catheter is a long medical device that is inserted into a body lumen such as a blood vessel and used for diagnosing or treating the body lumen.

[0003] Catheters with two or more lumens are known for purposes such as improving the vascular selectivity of guidewires. This type of catheter has, for example, a configuration in which multiple inner tubes, each with a lumen, are inserted into an outer tube and welded to the outer tube (see, for example, Patent Document 1). When the tubes constituting the catheter are welded together, the wall thickness of the tube may become thin, potentially reducing the strength of the tube. If the strength of a tube with a lumen is reduced, for example, there is a risk that the guidewire may unintentionally come out of the lumen.

[0004] Conventionally, catheters have been proposed in which a protective film is disposed between an inner tube and an outer tube or between a plurality of inner tubes in order to prevent a decrease in wall thickness due to welding between the tubes. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-213684 Summary of the Invention [Problem to be solved by the invention]

[0006] In the catheters of the above-described conventional configuration, there is room for improvement in the strength of the tube having the lumen.

[0007] This specification discloses a technique that can solve the above-mentioned problems. [Means for solving the problem]

[0008] The technology disclosed in this specification can be realized, for example, in the following forms.

[0009] (1) A catheter disclosed in this specification includes a first tube having a first lumen and a second tube having a second lumen. The first tube has an inner layer that forms the innermost layer of the first lumen, an outer layer that surrounds the inner layer, and a reinforcing layer sandwiched between the inner layer and the outer layer.

[0010] According to this catheter, the reinforcing layer sandwiched between the inner and outer layers can improve the strength of the first tube having the first lumen, thereby preventing, for example, the guidewire from accidentally coming out of the first lumen or the first lumen from collapsing and causing the guidewire to become stuck.

[0011] (2) The catheter may further include a connecting layer that covers at least a portion of the outer circumferential surfaces of the first tube and the second tube to connect the first tube and the second tube, and that has a melting point lower than that of the inner layer and the outer layer. This configuration can prevent the inner layer and the outer layer for the first tube from becoming thin due to welding, effectively improving the strength of the first tube and preventing the reinforcing layer sandwiched between the inner layer and the outer layer from being exposed.

[0012] (3) The catheter may have an elliptical outer periphery in cross section, which can improve passage through a lesion and operability of a combined device compared to a catheter having a circular outer periphery in cross section.

[0013] (4) In the catheter, the reinforcing layer may be a coil. By adopting this configuration, the coil as the reinforcing layer can improve the strength of the first tube while ensuring the flexibility required of the catheter.

[0014] (5) In the catheter, the reinforcing layer may be a first reinforcing layer, the inner layer may be a first inner layer, the outer layer may be a first outer layer, and the second tube may have a second inner layer constituting the innermost layer of the second lumen, a second outer layer surrounding the second inner layer, and a second reinforcing layer sandwiched between the second inner layer and the second outer layer. By adopting this configuration, the second reinforcing layer sandwiched between the second inner layer and the second outer layer can improve the strength of the second tube having the second lumen. Therefore, for example, it is possible to prevent the guidewire from accidentally coming out of the second lumen or the second lumen from collapsing, causing the guidewire to become stuck.

[0015] The technology disclosed in this specification can be realized in various forms, such as a catheter, a medical device equipped with a catheter, a method of manufacturing or using the same, etc. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is an explanatory diagram showing a schematic side view of a catheter according to an embodiment of the present invention. [Figure 2] FIG. 1 is an explanatory diagram showing a schematic longitudinal cross-sectional configuration of a catheter according to an embodiment of the present invention. [Figure 3] FIG. 1 is an explanatory diagram illustrating a schematic horizontal configuration of a catheter according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] A. Implementation: A-1. Configuration of catheter 10: 1 to 3 are explanatory diagrams schematically illustrating the configuration of a catheter 10 according to this embodiment. FIG. 1 illustrates the configuration of a side surface of the catheter 10, FIG. 2 illustrates the configuration of a longitudinal section (YZ section) of a portion of the catheter 10 (portion X1 in FIG. 1), and FIG. 3 illustrates the configuration of a transverse section (XY section) of the catheter 10 taken along the line III-III in FIG. 2. In each figure, the positive Z-axis direction corresponds to the distal end (distal side) inserted into the body, and the negative Z-axis direction corresponds to the proximal end (proximal side) manipulated by a surgeon such as a doctor. Although each figure illustrates the catheter 10 as a whole as being linear and substantially parallel to the Z-axis direction, at least a portion of the catheter 10 is flexible enough to be bent. In this specification, the distal end of the catheter 10 and each of its components will be referred to as the "tip," the distal end and its vicinity as the "tip portion," the proximal end as the "proximal end," and the proximal end and its vicinity as the "proximal portion."

[0018] The catheter 10 is a long medical device that is inserted into a body lumen such as a blood vessel and used for diagnosing or treating the body lumen. As shown in Figure 1, the catheter 10 has a shaft 20, a distal tip 30, and a connector 40.

[0019] The shaft 20 is a long tubular member. As shown in Figure 3, the outer periphery of a cross section of a predetermined portion of the shaft 20 (portion X1 in Figure 1) is elliptical. The elliptical shape is not limited to a mathematically strict elliptical shape, but includes any shape that resembles at least a circle that has been squashed in one direction. The shape (length and diameter) of the shaft 20 is designed appropriately depending on the purpose and location of use of the catheter 10, etc.

[0020] The shaft 20 is formed with two lumens (a first lumen L1 and a second lumen L2) extending along the longitudinal direction of the shaft 20. The first lumen L1 is a lumen for a guidewire. The second lumen L2 is a lumen for a guidewire. A distal opening 116 of the first lumen L1 is disposed at the distal end of the shaft 20 and connected to the distal tip 30, and a proximal opening 117 of the first lumen L1 is disposed in the peripheral wall at the intermediate portion of the shaft 20 and is open to the outside of the catheter 10. In other words, the first lumen L1 is a rapid exchange (RX) type lumen formed in the range from the distal end to the intermediate portion of the shaft 20. On the other hand, a distal opening 126 of the second lumen L2 is disposed at the distal end of the shaft 20, and a proximal opening 127 of the second lumen L2 is disposed at the proximal end of the shaft 20 and connected to the connector 40. That is, the second lumen L2 is an over-the-wire (OTW) type lumen formed over substantially the entire length (from the distal end to the proximal end) of the shaft 20. The configuration of the shaft 20 will be described in detail later.

[0021] The distal tip 30 is a cylindrical (hollow) member and is joined to the distal end of the shaft 20. Methods for joining the distal tip 30 and the shaft 20 include welding and adhesion using an adhesive. The distal tip 30 has an inner cavity that extends in the longitudinal direction of the catheter 10, and this inner cavity communicates with the first lumen L1 formed in the shaft 20. The distal tip 30 has a tapered shape, for example, with the outer diameter gradually decreasing towards the distal end.

[0022] The material constituting the distal tip 30 may be, for example, a resin material such as polyurethane, polyurethane elastomer, polyamide, or polyamide elastomer. Furthermore, these resin materials may be mixed with powder of a material that is difficult for X-rays to transmit (e.g., tungsten, gold, platinum, etc.) so that the material can be seen when irradiated with X-rays. Furthermore, the distal tip 30 may be provided with a marker made of a material that is difficult for X-rays to transmit.

[0023] The connector 40 is a member that is held by a doctor or other operator, and is connected to the base end of the shaft 20. The connector 40 has an inner cavity that extends in the longitudinal direction of the catheter 10, and the inner cavity communicates with a second lumen L2 formed in the shaft 20.

[0024] Next, a more detailed description will be given of the configuration of the shaft 20. The shaft 20 has a first tube 110, a second tube 120, and a connecting layer .

[0025] The first tube 110 is a tubular member having a first lumen L1. The first tube 110 is disposed in the range from the distal end to the intermediate portion of the shaft 20, and as a result, as described above, the first lumen L1 is formed in the range from the distal end to the intermediate portion of the shaft 20.

[0026] As shown in FIGS. 2 and 3 , the first tube 110 includes a first inner layer 111 that constitutes the innermost layer of the first lumen L1, a first outer layer 112 that surrounds the first inner layer 111, and a first reinforcing layer 113 that is sandwiched between the first inner layer 111 and the first outer layer 112. The first inner layer 111 and the first outer layer 112 are, for example, tubular members having an annular cross section. The first reinforcing layer 113 is a coil that is wound helically around the outer peripheral surface of the first inner layer 111. In this embodiment, the first reinforcing layer 113 is a loosely wound coil. The first reinforcing layer 113 is disposed over the entire length of the first tube 110. However, the first reinforcing layer 113 may be disposed only in a portion of the first tube 110 in the longitudinal direction (for example, a portion toward the distal end).

[0027] The second tube 120 is a tubular member having a second lumen L2. The second tube 120 is disposed over substantially the entire length (from the distal end to the proximal end) of the shaft 20, and as a result, as described above, the second lumen L2 is formed over substantially the entire length of the shaft 20.

[0028] As shown in FIGS. 2 and 3 , the second tube 120 includes a second inner layer 121 that constitutes the innermost layer of the second lumen L2, a second outer layer 122 that surrounds the second inner layer 121, and a second reinforcing layer 123 that is sandwiched between the second inner layer 121 and the second outer layer 122. The second inner layer 121 and the second outer layer 122 are, for example, tubular members having an annular cross section. The second reinforcing layer 123 is a coil that is spirally wound around the outer peripheral surface of the second inner layer 121. In this embodiment, the second reinforcing layer 123 is a loosely wound coil. The second reinforcing layer 123 is disposed over the entire length of the second tube 120. However, the second reinforcing layer 123 may be disposed only in a portion of the second tube 120 in the longitudinal direction (for example, a portion toward the distal end).

[0029] 3, in a cross section (XY cross section) of the shaft 20, the first tube 110 and the second tube 120 are arranged side by side in the Y-axis direction. The first tube 110 and the second tube 120 are in continuous contact with each other along the longitudinal direction of the shaft 20. In this embodiment, the outer diameter and the inner diameter of the first tube 110 and the second tube 120 are approximately the same.

[0030] The first inner layer 111 and the first outer layer 112 of the first tube 110 and the second inner layer 121 and the second outer layer 122 of the second tube 120 may be made of resin materials such as polyimide, polyamide, polyamide elastomer, polyolefin, polyester, polyester elastomer, nylon, and polytetrafluoroethylene. The materials constituting each of the above layers may be the same or different. The first reinforcing layer 113 and the second reinforcing layer 123 may be made of metal materials such as stainless steel or Ni-Ti alloy, or resin materials such as PEEK.

[0031] The connecting layer 130 is a layer that covers at least a portion of the outer circumferential surfaces of the first tube 110 and the second tube 120 to connect the first tube 110 and the second tube 120. As shown in FIG. 3 , in the present embodiment, in a transverse cross section (XY cross section) of the shaft 20, the first tube 110 and the second tube 120 are exposed to the outside at both ends in the direction in which the first tube 110 and the second tube 120 are aligned (Y-axis direction) without being covered by the connecting layer 130. Note that the entire outer circumferential surfaces of the first tube 110 and the second tube 120 may be covered by the connecting layer 130. Furthermore, a core wire 50 is embedded in the connecting layer 130. The core wire 50 extends along the longitudinal direction of the shaft 20.

[0032] The material constituting the connecting layer 130 may be, for example, a resin material such as polyamide, polyamide elastomer, polyolefin, polyester, polyester elastomer, or nylon. The melting point of the connecting layer 130 is preferably lower than the melting points of the first inner layer 111 and first outer layer 112 of the first tube 110 and the second inner layer 121 and second outer layer 122 of the second tube 120. The material constituting the core wire 50 may be, for example, a metal material such as stainless steel, Ni-Ti alloy, or cobalt chromium alloy.

[0033] The shaft 20 having such a configuration can be manufactured, for example, as follows. First, a core is covered with the first inner layer 111 for the first tube 110, and a coil is wound around the outer peripheral surface of the first inner layer 111 as the first reinforcing layer 113. Thereafter, the first outer layer 112 is covered so as to cover the first inner layer 111 and the first reinforcing layer 113, and is welded while being compressed using a shrink tube. This produces the first tube 110 having the first reinforcing layer 113 sandwiched between the first inner layer 111 and the first outer layer 112. The second tube 120 is manufactured in a similar manner.

[0034] Next, the first tube 110, the second tube 120, and the core wire 50 are coated with a material for forming the connecting layer 130 so as to integrally cover them, and then the material is welded while being compressed using a shrink tube. This forms the connecting layer 130 that covers at least a portion of the outer circumferential surfaces of the first tube 110 and the second tube 120 and connects the first tube 110 and the second tube 120. The welding temperature at this time is set, for example, to a temperature higher than the melting point of the connecting layer 130 but lower than the melting points of the first inner layer 111 and the first outer layer 112 for the first tube 110 and the second inner layer 121 and the second outer layer 122 for the second tube 120. By setting the welding temperature in this manner, the first inner layer 111 and the first outer layer 112 for the first tube 110 and the second inner layer 121 and the second outer layer 122 for the second tube 120 do not melt during welding, and maintain their shape (outer diameter and wall thickness). 3, the coupling layer 130 flows out from both ends in the direction in which the first tube 110 and the second tube 120 are aligned (Y-axis direction). As a result, the outer periphery of the manufactured shaft 20 becomes elliptical in cross section.

[0035] A-2. Advantages of this embodiment: As described above, the catheter 10 of this embodiment includes the first tube 110 having the first lumen L1 and the second tube 120 having the second lumen L2. The first tube 110 includes the first inner layer 111 that constitutes the innermost layer of the first lumen L1, the first outer layer 112 that surrounds the first inner layer 111, and the first reinforcing layer 113 that is sandwiched between the first inner layer 111 and the first outer layer 112.

[0036] As described above, in the catheter 10 of this embodiment, the strength of the first tube 110 having the first lumen L1 can be improved by the first reinforcing layer 113 sandwiched between the first inner layer 111 and the first outer layer 112. This makes it possible to prevent, for example, the guidewire from accidentally coming out of the first lumen L1 or the first lumen L1 from collapsing and causing the guidewire to become stuck.

[0037] The catheter 10 of this embodiment also includes a connecting layer 130. The connecting layer 130 covers at least a portion of the outer circumferential surfaces of the first tube 110 and the second tube 120 to connect the first tube 110 and the second tube 120. The melting point of the connecting layer 130 is lower than the melting points of the first inner layer 111 and the first outer layer 112 for the first tube 110. Therefore, the catheter 10 of this embodiment can prevent the first inner layer 111 and the first outer layer 112 for the first tube 110 from becoming thin due to welding, thereby effectively improving the strength of the first tube 110 and preventing the first reinforcing layer 113 sandwiched between the first inner layer 111 and the first outer layer 112 from being exposed.

[0038] Furthermore, the catheter 10 of this embodiment has an elliptical outer periphery in cross section of the catheter 10. Therefore, the catheter 10 of this embodiment can improve passage through a lesion and operability of a combined device compared to a catheter having a circular outer periphery in cross section.

[0039] Furthermore, in the catheter 10 of this embodiment, the first reinforcing layer 113 is a coil. Therefore, according to the catheter 10 of this embodiment, the coil as the first reinforcing layer 113 can improve the strength of the first tube 110 while ensuring the flexibility required of the catheter 10.

[0040] Furthermore, in the catheter 10 of this embodiment, the second tube 120 has a second inner layer 121 that constitutes the innermost layer of the second lumen L2, a second outer layer 122 that surrounds the second inner layer 121, and a second reinforcing layer 123 that is sandwiched between the second inner layer 121 and the second outer layer 122. Therefore, according to the catheter 10 of this embodiment, the second reinforcing layer 123 that is sandwiched between the second inner layer 121 and the second outer layer 122 can improve the strength reduction of the second tube 120 that has the second lumen L2. Therefore, for example, it is possible to prevent the guidewire from unintentionally coming out of the second lumen L2 or the second lumen L2 from being crushed and causing the guidewire to become stuck.

[0041] B. Variations: The technology disclosed in this specification is not limited to the above-described embodiments, and can be modified into various forms without departing from the spirit thereof, for example, the following modifications are also possible.

[0042] The configuration of the catheter 10 in the above embodiment is merely an example and can be modified in various ways. For example, in the above embodiment, the first reinforcing layer 113 for the first tube 110 and the second reinforcing layer 123 for the second tube 120 are loosely wound coils, but the first reinforcing layer 113 and the second reinforcing layer 123 may be tightly wound coils or may be configured other than a coil (for example, a braid, a tube, etc.).

[0043] In the above embodiment, the outer periphery of the catheter 10 in cross section is elliptical, but the outer periphery may be another shape (for example, circular). Also, in the above embodiment, the outer diameters and inner diameters of the first tube 110 and the second tube 120 are approximately the same, but the outer diameters and inner diameters of the first tube 110 and the second tube 120 may be different from each other.

[0044] In the above embodiment, both the first tube 110 and the second tube 120 are configured to have a reinforcing layer sandwiched between an inner layer and an outer layer, but only one of the first tube 110 and the second tube 120 may have such a configuration.

[0045] In the above embodiment, the catheter 10 has two lumens, but the catheter 10 may have three or more lumens. In such a case, if at least one of the three or more lumens is configured as a tube having a lumen and a reinforcing layer sandwiched between an inner layer and an outer layer, the strength of the tube can be improved. At least one of the lumens does not have to be used as a guidewire. For example, a certain lumen may function as a flow path for a fluid (e.g., a medicinal solution).

[0046] In the above embodiment, the core wire 50 is embedded in the coupling layer 130, but the core wire 50 may be omitted.

[0047] In the above embodiment, the catheter 10 inserted into a blood vessel has been used as an example, but the technology disclosed in this specification is similarly applicable to catheters generally inserted into biological lumens (digestive organs such as the bile duct, gallbladder, pancreas, esophagus, duodenum, small intestine, large intestine, etc., blood vessels, ureters, trachea, etc.). [Explanation of symbols]

[0048] 10: Catheter 20: Shaft 30: Distal tip 40: Connector 50: Core wire 110: First tube 111: First inner layer 112: First outer layer 113: First reinforcing layer 116: Opening 117: Opening 120: Second tube 121: Second inner layer 122: Second outer layer 123: Second reinforcing layer 126: Opening 127: Opening 130: Connecting layer L1: First lumen L2: Second lumen

Claims

1. a first tube having a first lumen; a second tube having a second lumen; a connecting layer connecting the first tube and the second tube; a core wire embedded in the connecting layer; Equipped with The first tube is a first inner layer constituting the innermost layer of the first lumen; a first outer layer surrounding the first inner layer; a first reinforcing layer sandwiched between the first inner layer and the first outer layer; and The second tube is a second inner layer constituting the innermost layer of the second lumen; a second outer layer surrounding the second inner layer; a second reinforcing layer sandwiched between the second inner layer and the second outer layer; and A catheter, wherein the melting point of the connecting layer is lower than the melting point of the first inner layer, the melting point of the first outer layer, the melting point of the second inner layer, and the melting point of the second outer layer.

2. A catheter according to claim 1, A catheter, wherein in at least one cross section of the catheter, the first tube and the second tube are exposed to the outside of the connecting layer at both ends in the direction in which the first tube and the second tube are aligned.

3. The catheter according to claim 1 or 2, A catheter having an outer periphery in cross section that is elliptical.

4. The catheter according to claim 1 or 2, A catheter, wherein the reinforcing layer is a coil.

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