catheter

Abstract

To provide a catheter comprising a shaft with a thin diameter, while still comprising a marker.SOLUTION: A catheter 1 comprises: an inner layer 4; a wire reinforcement layer 5 covering the inner layer 4; an outer layer 6 formed on a radially outside of the wire reinforcement layer 5; and a marker 7 including a material having radioparency lower than that of the outer layer 6 and being covered with the outer layer 6. The wire reinforcement layer 5 is formed of wire strands 5a arranged interposing each interval. The marker 7 has a main body part 7a in at least a part of a center region in an axial direction. At least a part of the main body part 7a is provided in each interval between adjacent wire strands 5a and comes into a radially inside relative to an external surface of the wire reinforcement layer 5.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a catheter having a marker for identifying an insertion position within a body cavity. [Background technology]

[0002] Conventionally, catheters equipped with markers with low X-ray transmittance have been used to identify the insertion position within a body cavity. A specific application of the marker is to irradiate the catheter insertion site with X-rays while the catheter is inserted into the body cavity, and to detect the marker part through which X-rays do not penetrate, thereby determining the insertion position of the catheter.

[0003] For example, Patent Document 1 discloses a catheter that allows for good insertion of a guidewire. The catheter in this document includes an inner layer (referred to as the inner layer in the document), a reinforcing layer in which multiple wires are woven, and an outer layer. The document also describes that the outer layer of the shaft (referred to as the outer layer in the document) contains an X-ray opaque material to function as a marker. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Utility Model Registration No. 3179894 Summary of the Invention [Problem to be solved by the invention]

[0005] However, since the marker in this document was included in the outer layer as described above, the flexibility was sometimes impaired by the X-ray opaque material. On the other hand, when a member having a fixed shape such as a ring is disposed as a marker outside the reinforcing layer and inside the outer layer, the shaft expands by the thickness of the marker, which may limit insertion into a small-diameter body cavity.

[0006] The present invention has been made in consideration of the above problems, and provides a catheter having a marker and a thin-diameter shaft. [Means for solving the problem]

[0007] According to the present invention, there is provided a catheter comprising an inner layer which is formed hollow and extends in an axial direction, and a wire reinforcement layer which covers the inner layer, an outer layer which is formed radially outward of the catheter relative to the wire reinforcement layer, and a marker which includes a material having a lower X-ray transmittance than the outer layer and is covered by the outer layer, the wire reinforcement layer being composed of wire strands which are arranged with gaps between them, The marker The one portion of the marker is inserted into the gap of the wire strand. the The other portion is formed radially outward of the wire reinforcing layer and covers at least a portion of the wire strand. The thickness of the portion of the marker is the The thickness of the one portion is larger than that of the other portion, and the thickness of the one portion and the the The other portion is formed as a single continuous piece of material, and the one portion and the the Other parts are X-ray opaque particles is distributed The X-ray transmittance is lower than that of the outer layer. The marker is configured to include a resin, and the one portion and the the The other parts are 60 to 90 wt% of the above. radiopaque A catheter is provided that is formed containing particles, the portion of the marker being in contact with the inner layer. Effect of the Invention

[0008] According to the present invention, a catheter having a marker and a thin-diameter shaft can be provided. [Brief description of the drawings]

[0009] [Figure 1] 1 is an overall view of a catheter according to an embodiment of the present invention. [Diagram 2]2 is an explanatory diagram showing a cross section of the outer layer of part II in FIG. 1, illustrating the wire strands and markers located inside the outer layer. [Diagram 3] FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 2, and is a schematic explanatory view showing a laminated structure of an inner layer, a wire reinforcement layer, an outer layer, and a marker. [Figure 4] FIG. 13 is a schematic explanatory diagram showing a laminated structure of an inner layer, a wire reinforcement layer, an outer layer, and a marker of a catheter equipped with a manipulation wire according to a first modified example. [Diagram 5] FIG. 13 is a diagram showing a marker according to a second modified example, illustrating a cross section of the outer layer of part II in FIG. 1 and showing the wire strands and the marker located inside the outer layer. [Figure 6] FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. 5, and is a schematic explanatory view showing a laminated structure of an inner layer, a wire reinforcement layer, an outer layer, and a marker. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The embodiment described below is merely an example for facilitating understanding of the present invention, and is not intended to limit the present invention. In other words, the shapes, dimensions, arrangements, and other aspects of the components described below may be modified or improved without departing from the spirit of the present invention, and the present invention naturally includes equivalents thereof. In addition, in all the drawings, the same components are denoted by the same reference numerals, and duplicated explanations are omitted as appropriate. Note that in each drawing, the dimensional ratio is adjusted so as to clearly show the difference in the characteristic configuration of each part, and therefore may differ from the actual dimensional ratio.

[0011] <Summary> First, an overview of the catheter according to this embodiment will be described mainly with reference to Fig. 1 to Fig. 3. Fig. 1 is an overall view of a catheter 1 according to an embodiment of the present invention. Fig. 2 is an explanatory diagram showing a cross section of the outer layer 6 of part II in Fig. 1, illustrating the wire strands 5a and markers 7 located inside the outer layer 6, and Fig. 3 is a cross section taken along line III-III in Fig. 2, and is a schematic explanatory diagram illustrating the layered structure of the inner layer 4, wire reinforcement layer 5, outer layer 6, and markers 7.

[0012] The catheter 1 of this embodiment comprises an inner layer 4 which is hollow and extends in the axial direction, a wire reinforcement layer 5 which covers the inner layer 4, an outer layer 6 which is formed radially outward from the wire reinforcement layer 5, and a marker 7 which contains a material having a lower X-ray transmittance than the outer layer 6 and is covered by the outer layer 6. The wire reinforcing layer 5 is composed of wire strands 5a arranged with gaps therebetween. The marker 7 has a main body portion 7a in at least a part of an area located in the center in the axial direction. At least a part of the main body portion 7a is disposed in the gap between adjacent wire strands 5a and is located radially inward of the outer surface of the wire reinforcing layer 5.

[0013] According to the above configuration, at least a portion of the main body 7a of the marker 7 is disposed in the gap between adjacent wire strands 5a and extends radially inward from the outer surface of the wire reinforcement layer 5, so that even if the marker 7 is provided on the outside of the wire reinforcement layer 5, the catheter 1 (shaft 3) can be prevented from bulging radially outward.

[0014] The "gaps" of the wire strands 5a may be formed by pitch-winding a single wire strand 5a into a coil shape and winding it around the inner layer 4. In this case, the "gaps between adjacent wire strands 5a" refers to the gaps between adjacent loops of a single wire strand 5a. Furthermore, as described later, the wire reinforcing layer 5 may be formed by winding a plurality of wire strands 5a around the inner layer 4 in a multi-filament coil or mesh coil shape, with the wire strands 5a spaced apart from one another in the axial direction.

[0015] <Configuration> Next, the configuration of a catheter 1 according to this embodiment will be described with reference mainly to FIGS. The catheter 1 comprises a handle 2 which is a gripping portion, and a flexible tubular shaft 3 whose base end is connected to the handle 2. As described above, the catheter 1 (shaft 3) comprises an inner layer 4 that is hollow and extends in the axial direction, a wire reinforcement layer 5 that covers the inner layer 4, an outer layer 6 that is formed radially outward from the wire reinforcement layer 5, and a marker 7 that is covered by the outer layer 6.

[0016] (Inner layer) The inner layer 4 according to this embodiment is made of a nylon-based elastomer resin, and is hollow so that a medical device such as a guide wire or an embolization coil can be passed through it. An adhesive (not shown) is applied to the outer surface of the inner layer 4. The adhesive allows the inner layer 4 to maintain an appropriate adhesive state with the wire strand 5a, the marker 7, and a part of the outer layer 6.

[0017] (Wire reinforcement layer) The wire reinforcement layer 5 according to this embodiment provides rigidity and shapeability to the shaft 3, and is a mesh made up of a plurality of wire strands 5a that cross each other in two directions to form a two-layer structure. The wire strands 5a according to this embodiment have a diameter of 15 μm, which means that the wire reinforcement layer 5 has a maximum thickness of 30 μm. An adhesive (not shown) is applied to the radially outer surface of the wire strand 5a in the region where the marker 7 is attached. This adhesive ensures that the marker 7 is appropriately adhered to the wire strand 5a.

[0018] (outer layer) The outer layer 6 according to this embodiment is formed by adding 40 Wt % of X-ray opaque particles (e.g., barium sulfate) to a nylon-based elastomer resin. Since the outer layer 6 has a property of being difficult to transmit X-rays, though not to the same extent as the markers 7, the shaft 3 including the outer layer 6 is configured to be observable over its entire length by irradiating it with X-rays.

[0019] (marker) The marker 7 according to this embodiment is opaque to X-rays, and its position is identified by irradiation with X-rays. As described above, the marker 7 has a main body portion 7a in at least a part of an area located in the center in the axial direction, and end portions 7b located at both ends in the axial direction. The marker 7 is made of a resin containing dispersed particles with low X-ray transmittance. The main body 7a of the marker 7 is embedded in a part of the adjacent wire strand 5a. In other words, at least a part of the adjacent wire strand 5a is embedded in the marker 7. As in the above configuration, by molding the markers 7 from resin, the wire strands 5a can be embedded in the markers 7, and the markers 7 can be easily disposed in the gaps between the wire strands 5a.

[0020] Specifically, the marker 7 is formed by kneading X-ray opaque particles (for example, barium sulfate) in a small amount of nylon-based elastomer resin used as a binder resin in a concentration higher than that of the outer layer 6 (for example, 60 to 90 Wt %). The X-ray impermeable material used for the outer layer 6 and the markers 7 may be barium sulfate, tungsten, platinum or a platinum-iridium alloy, or a mixture of these with other metal elements.

[0021] A portion 7aa of the marker 7 enters into a gap between the wire strands 5a. Specifically, the marker 7 is pressed against the wire reinforcing layer 5, so that the portion 7aa of the marker 7 fits into the mesh of the wire reinforcing layer 5. The other portion 7ab of the marker 7 is formed radially outward of the wire reinforcing layer 5 and covers at least a portion of the wire reinforcing layer 5 (the bare wire 5a). The thickness of the portion 7aa of the marker 7 is greater than the thickness of the other portion 7ab.

[0022] According to the above configuration, the thickness of the portion 7aa of the marker 7 that penetrates into the gaps in the wire strand 5a is greater than the thickness of the other portion 7ab that covers the wire reinforcement layer 5, so that the outer diameter of the shaft 3 of the catheter 1 can be made thinner than in a configuration in which the marker 7 does not penetrate into the gaps in the wire strand 5a. It is preferable that the outer surface of the marker 7 is equal to (including approximately equal to) the outer diameter of the wire reinforcement layer 5 (height from the outer surface of the inner layer 4), but as described above, the marker 7 may be formed to protrude radially outward from the wire reinforcement layer 5.

[0023] Note that the outer layer 6 may be made of nylon-based elastomer resin or the like to which 40 Wt% barium sulfate has been added, while, contrary to the configuration according to the above embodiment, no X-ray opaque particles such as barium sulfate may be added, or the amount added may be reduced, to the marker 7. Even with such a configuration, X-rays may be more easily transmitted through the portion of the shaft 3 that overlaps the marker 7 than the other portions, and the overlapping portion may be made more noticeable, thereby making it possible to identify the position of the marker 7. With this configuration, the position of the marker 7 is identified by the contrast with the X-ray impermeable outer layer 6, resulting in poor visibility. However, since it is not necessary to add barium sulfate or the like to the marker 7 or the amount of barium sulfate added can be reduced, the shaft 3 can be manufactured easily and manufacturing costs can be reduced.

[0024] [First Modification] Next, a catheter 1X according to a first modified example will be described with reference mainly to Fig. 4. Fig. 4 is a schematic explanatory diagram showing a laminated structure of an inner layer 4, a wire reinforcement layer 5, an outer layer 6, and a marker 7 of a catheter 1X including an operating wire 9 according to a first modified example.

[0025] The shaft 13 of the catheter 1X in this example includes a tip marker 8 provided at the tip, an operating wire 9 extending through the inside of the outer layer 6 to the handle 2, and a sub-lumen tube 10 provided within the outer layer 6 and covering a portion of the operating wire 9.

[0026] The tip marker 8 is adhered to the inner layer 4 by an adhesive (not shown). The sub-lumen tube 10 allows a part of the operating wire 9 to slide within the outer layer 6, and forms a hollow portion through which a part of the operating wire 9 passes. Moreover, the sub-lumen tube 10 according to this example has flexibility, and is disposed so as to contact the outer surface of the marker 7. The operating wire 9 passes through the inside of the sub-lumen tube 10 , protrudes from the tip of the sub-lumen tube 10 , and is fixed to the outer surface of the tip marker 8 .

[0027] To be opaque to X-rays, the marker 7 and the tip marker 8 need to have a certain thickness. As described in the above embodiment, a portion 7aa of the marker 7 is fitted into the mesh of the wire reinforcement layer 5. Therefore, when the marker 7 and the tip marker 8 are disposed so as to contact the inner layer 4, their outer surfaces can be disposed at the same height (including approximately the same height) from the inner layer 4. Therefore, a difference in height between the marker 7 and the tip marker 8 is unlikely to occur, and it is possible to suppress the occurrence of sliding resistance caused by the operating wire 9 rubbing against the inner wall surface of the sub-lumen tube 10. For this reason, the operating wire 9 can be smoothly operated, and the linkage with bending of the tip portion of the shaft 13 can be improved.

[0028] For example, a configuration may be adopted in which the tip marker 8 is formed in a rigid ring shape, and the tip of the wire reinforcement layer 5 is disposed radially inward of the tip marker 8. For example, in this configuration, the tip marker 8 is fixed to the inner layer 4 together with the tip of the wire reinforcement layer 5 by crimping. According to this configuration, the crimped tip marker 8 presses the tip of the wire reinforcement layer 5 against the inner layer 4, thereby suppressing the tip of the wire strand 5a that constitutes the wire reinforcement layer 5 from unfolding.

[0029] When such a configuration is adopted and the marker 7 and the tip marker 8 have the same thickness, the wire reinforcement layer 5 is arranged radially inside the tip marker 8, so that the outer surface of the tip marker 8 is positioned radially outward compared to the outer surface of the marker 7. In this case, in order to reduce the diameter of the shaft 13 while ensuring the thickness of the outer layer 6 radially outward from the tip marker 8, it is preferable to make the thickness of the tip marker 8 thinner than the thickness of the marker 7. Specifically, it is preferable to make the thickness of the tip marker 8 thinner than the thickness of the marker 7 by the thickness of the wire reinforcement layer 5, since this makes the outer surface heights of the marker 7 and the tip marker 8 uniform.

[0030] [Second modified example] Finally, a catheter 1Y according to a second modified example will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a diagram showing a marker 11 according to the second modified example, and is an explanatory diagram showing a cross section of the outer layer 6 of part II in Fig. 1, and showing the wire strands 5a and the marker 11 located inside the outer layer 6. Fig. 6 is a diagram showing a cross section taken along line VI-VI in Fig. 5, and is a schematic explanatory diagram showing the layered structure of the inner layer 4, the wire reinforcing layer 5, the outer layer 6, and the marker 11.

[0031] The marker 11 according to this embodiment is formed into a plurality of segments (diamond-shaped segments). By forming the marker 11 into segments in this manner, a material with a high content of low X-ray transmittance can be disposed in the gaps between the wire strands 5a without being mixed into the resin. Here, the segment-shaped markers 11 refer to markers that are dispersed and arranged in a plurality of closed regions 15, which will be described later, formed by the wire strands 5a. The term "segment-shaped" includes not only diamond-shaped segments shown in Fig. 5 in this embodiment, but also polygonal segments and disk shapes.

[0032] In detail, the marker 11 is formed by cutting into a diamond shape a thin film of a metal foil such as platinum or tungsten, which has a lower X-ray transmittance than nylon-based elastomer resin, or a mixture of these metals with other metal elements. In this way, since the marker 11 is formed by cutting a metal foil, it does not contain resin and is therefore more impermeable to X-rays than the marker 7 according to the above embodiment. Therefore, by irradiating the shaft 3 with X-rays, the position of the marker 11 can be clearly identified.

[0033] The markers 11 are constituted by a plurality of divided wire strands 5a, and are formed so as to extend as a whole in the circumferential direction of the inner layer 4. In this way, the markers 11 are formed so as to extend in the circumferential direction of the inner layer 4, and thus can block the transmission of X-rays integrally over a wide range in the circumferential direction, improving visibility.

[0034] In particular, the marker 11 according to this embodiment is disposed radially inward from the radially outer surface of the wire reinforcement layer 5 so as to fit in the gap between adjacent wire strands 5a, as shown in FIG. According to the above configuration, the marker 11 protrudes from the outer surface of the wire reinforcement layer 5, and the outer layer 6 covering the marker 11 protrudes, thereby preventing an increase in the outer diameter of the catheter 1Y (shaft 23).

[0035] The wire reinforcement layer 5 has a mesh structure made up of wire strands 5a wound in different directions at intervals, and has a plurality of closed regions 15 formed by the mesh structure as shown in FIG. The marker 11 is disposed so as to be contained within at least a part of the closed region 15 of the wire reinforcement layer 5. Specifically, the marker 11 is formed to have an area smaller than the area of ​​the closed region 15 when viewed in a direction perpendicular to the circumferential surface of the shaft 23. In this way, by arranging the marker 11 so that it fits within at least a portion of the closed area 15 of the wire reinforcement layer 5, the marker 11 can be arranged suitably even in a mesh structure rather than a multi-strand coil structure made of multiple wire strands 5a in the same direction.

[0036] The method of manufacturing the catheter 1Y (shaft 23) having the marker 11 includes winding the wire strands 5a around the inner layer 4 in a mesh shape to form the wire reinforcement layer 5, and then adhesively bonding the above-mentioned cut diamond-shaped thin film into the "mesh" of the wire reinforcement layer 5 to form the marker 11 on the inner layer 4. Thereafter, the outer layer 6 is formed on the wire reinforcement layer 5 and the marker 11 to manufacture the catheter 1Y. Note that the adhesive that bonds the marker 11 to the inner layer 4 is omitted in FIG. 6.

[0037] In the above embodiment, the wire reinforcement layer 5 has been described as being formed by wire strands 5a (also called braid) formed in a mesh shape, but the wire reinforcement layer of the present invention is not limited to such a configuration. For example, the wire reinforcement layer 5 may be formed of a multi-strand coil including wire strands 5a wound in a spiral shape with gaps in one direction (wound in parallel in the same direction as the winding direction). In this case, it is preferable that the marker 11 is formed in a spiral shape, arranged between the wire strands 5a, and provided so as to fit between the wire strands 5a in a partial region of the shaft 3 in the longitudinal direction. In this case as well, the same effects as those of the catheter 1 having the mesh-like wire reinforcement layer 5 and the marker 7 can be achieved.

[0038] The present embodiment and the present manufacturing method include the following technical ideas. (1) an inner layer formed to be hollow and extending in an axial direction; a wire reinforcing layer covering the inner layer; an outer layer formed radially outward of the wire reinforcement layer; a marker including a material having a lower X-ray transmittance than the outer layer and covered by the outer layer; The wire reinforcing layer is made of wire strands arranged with gaps between them, The marker has a body portion in at least a portion of a region central in the axial direction, A catheter characterized in that at least a portion of the main body is disposed in a gap between adjacent wire strands and extends radially inward beyond an outer surface of the wire reinforcement layer. (2) a portion of the marker penetrates into the gap of the wire strand; Another portion of the marker is formed radially outward from the wire reinforcement layer and covers at least a portion of the wire reinforcement layer, The catheter according to (1), wherein the thickness of the one portion of the marker is greater than the thickness of the other portion. (3) The marker is configured to include a resin having particles with low X-ray transmittance dispersed therein, The catheter according to (1) or (2), wherein at least a portion of the adjacent wire strands is embedded in the marker. (4) The catheter according to (1), wherein the marker is formed into multiple pieces. (5) The wire reinforcement layer has a mesh structure formed of the wire strands wound at intervals in different directions, and has a plurality of closed regions formed by the mesh structure; The catheter according to (4), wherein the marker is disposed so as to be contained within at least a portion of the closed region of the wire reinforcement layer. (6) The wire reinforcement layer is formed of a multi-filament coil including the wire strand wound in a spiral shape with gaps in between in one direction, The catheter according to (1), wherein the marker is formed in a spiral shape. (7) A catheter described in any one of (4) to (6), wherein the marker is composed of multiple sections of the wire strand and is formed so as to extend as a whole in the circumferential direction of the inner layer. (8) A catheter described in any one of (4) to (7), wherein the marker is located radially inward from the radially outer surface of the wire reinforcement layer and is arranged to fit within a gap between adjacent wire strands. [Explanation of symbols]

[0039] 1, 1X, 1Y Catheter 2 Handle 3, 13, 23 Shaft 4 Inner layer 5 Wire Reinforcement Layer 5a Wire strand 6 outer layer 7. Markers 7a Main body 7aa part 7ab Other parts 7b End 8 Tip Marker 9 Operating Line 10 Sublumen Tube 11 Marker 15 Closed region

Claims

1. An inner layer that is formed hollow and extends in an axial direction; a wire reinforcement layer covering the inner layer, an outer layer formed radially outward of the catheter relative to the wire reinforcement layer; a marker including a material having a lower X-ray transmittance than the outer layer and covered by the outer layer; The wire reinforcing layer is made of wire strands arranged with gaps between them, A portion of the marker penetrates into the gap of the wire strand, The other portion of the marker is formed radially outward from the wire reinforcing layer and covers at least a portion of the wire strand, The thickness of the one portion of the marker is greater than the thickness of the other portion of the marker, The one portion and the other portion are formed as a single continuous piece of material, the one portion and the other portion of the marker are configured to include a resin having X-ray opaque particles dispersed therein and having a lower X-ray transmittance than the outer layer, the one portion and the other portion of the marker are formed containing 60 to 90 wt % of the X-ray opaque particles; A catheter, wherein the portion of the marker is in contact with the inner layer.

2. The inner layer has an adhesive on an outer surface thereof; The catheter of claim 1 , wherein the portion of the marker is in contact with the inner layer by being adhered to the inner layer by the adhesive.

3. The wire reinforcement layer has a mesh structure formed of a plurality of the wire strands wound in different directions, 3. The catheter according to claim 1, wherein the other portion covers the wire strand at an intersection of the plurality of wire strands, and an outer surface of the other portion is at the same height as an outer surface of the one portion.

4. The catheter according to claim 2 or 3, wherein the other portion of the marker and the radially outer surface of the wire strand are bonded with an adhesive.

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