Extension guide catheter

Abstract

Provided is an extension guide catheter (1) for a guide catheter. The extension guide catheter (1) includes: a tubular body (2) that has a lumen (3) extending in the lengthwise axial direction; and a linear member (12) that extends on the proximal side from the tubular body (2). A ring- or spiral-shaped groove section extending in the circumferential direction is provided to the inner side surface of a distal-side end section (6) of the tubular body (2). The thickness of the tubular body (2) is formed thin at a portion where the groove section is provided.

Description

Technical Field

[0001] The present invention relates to an extension guide catheter for a guide catheter, and more specifically, relates to an extension guide catheter that is inserted into a guide catheter and used by being extended from a distal opening of the guide catheter.

Background Art

[0002] For ischemic heart diseases such as angina pectoris and myocardial infarction, percutaneous coronary intervention (PCI) is performed, which uses intravascular treatment instruments such as stents and balloons to dilate the stenotic portion of the coronary artery of the heart and increase blood flow. At this time, after the distal end of the tubular guide catheter is inserted into the entrance of the coronary artery and indwelled, the intravascular treatment instrument is delivered through the guide catheter, so that the insertability of the intravascular treatment instrument toward the peripheral side of the coronary artery is generally enhanced. However, when the backup force is small and the indwelling is unstable, the distal end of the guide catheter may come off from the entrance of the coronary artery. In that case, an extension guide catheter with a smaller diameter may be inserted into the guide catheter, and the extension guide catheter may be extended from the distal opening of the guide catheter to improve the backup force.

[0003] Various such extension guide catheters are known. For example, Patent Document 1 discloses a guide extension guide catheter having a proximal member including an extension portion, a collar member attached to the extension portion, and a distal sheath member attached to the collar member. Patent Document 2 discloses a guide extension catheter including a push member having a portion with a first surface formed with a groove and a second surface opposite thereto, and a distal shaft having a passage adjacent to the push member. Patent Document 3 discloses an extension catheter including a tubular portion, a first tapered portion located on the proximal side of the tubular portion, and a second tapered portion located on the proximal side of the first tapered portion, wherein an angle formed by the first tapered surface of the first tapered portion and the axial direction of the tubular portion is 90° to 145°, and an angle formed by the second tapered surface of the second tapered portion and the axial direction of the tubular portion is 120° to 175°. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2018 / 075700 [Patent Document 2] International Publication No. 2017 / 214209 [Patent Document 3] International Publication No. 2020 / 162286 [Overview of the project] [Problems that the invention aims to solve]

[0005] An extension guide catheter is used by being inserted into a guide catheter. However, when advancing a treatment device such as an intravascular treatment instrument from the guide catheter through the extension guide catheter, the distal end of the extension guide catheter may be located in a curved portion of the body cavity. In this case, there is a concern that the distal end of the extension guide catheter will bend in the curved portion of the body cavity, causing a significant distortion of the cross-sectional shape of the lumen. As a result, it may become difficult for the treatment device, such as an intravascular treatment instrument, to pass smoothly through the distal end of the extension guide catheter, potentially hindering the extension of the treatment device from the distal opening of the extension guide catheter. The present invention has been made in view of the above circumstances, and its object is to provide an extension guide catheter that suppresses significant distortion of the cross-sectional shape of the lumen even when the distal end of the extension guide catheter is bent. [Means for solving the problem]

[0006] The extension guide catheter of the present invention is as follows: [1] An extension guide catheter for a guide catheter, comprising a cylindrical body having a lumen extending in the longitudinal direction and having a proximal opening and a distal opening, and a linear member fixed to the cylindrical body and extending proximal to the proximal opening of the cylindrical body, wherein the inner surface of the distal end of the cylindrical body is provided with an annular or helical groove extending in the circumferential direction, and the wall thickness of the cylindrical body is formed to be thinner in the portion where the groove is provided.

[0007] As described above, the distal end of the extension guide catheter of the present invention is formed as a tubular body, making the distal end of the extension guide catheter more flexible and easier to bend, allowing it to advance smoothly through the guide catheter and body cavity. Furthermore, even if the distal end of the tubular body is located in a curved portion of the body cavity, kinking that causes the lumen to collapse at the distal end of the tubular body is less likely to occur, and the cross-sectional shape of the lumen in that portion is suppressed to the extent that it may be significantly distorted. As a result, it becomes easier to extend treatment devices such as endovascular treatment instruments through the distal end of the tubular body and out through the distal opening.

[0008] [2] The extension guide catheter according to [1], wherein the distal end of the tubular body has a flat outer surface in the longitudinal axial area where the groove is provided. As described above, if the distal end of the tubular body is formed, when advancing the extension guide catheter within the guide catheter, the distal end of the tubular body will not get caught on the guide catheter or the inner wall of the body cavity, making it easier to smoothly advance the extension guide catheter within the guide catheter or body cavity.

[0009] [3] The extension guide catheter according to [1] or [2], wherein the outer surface of the distal end of the cylindrical body has an inclined portion that slopes toward the longitudinal axis of the cylindrical body toward the distal side. As described above, if an inclined portion is formed on the outer surface of the distal end of the cylindrical body, it becomes easier to smoothly advance the distal end of the cylindrical body within the guide catheter or body cavity, and the distal end of the cylindrical body can bend and advance more smoothly in curved sections of the guide catheter or body cavity.

[0010] [4] The distal end of the cylindrical body has a first section including the distal end of the cylindrical body and a second section proximal thereto, with respect to the longitudinal axis, and the outer surface of the distal end of the cylindrical body is formed parallel to the longitudinal axis in the second section and inclined toward the longitudinal axis of the cylindrical body toward the distal side in the first section, as described in any of [1] to [3]. [5] The distal end of the cylindrical body has a first section including the distal end of the cylindrical body and a second section proximal thereto with respect to the longitudinal axis, and the outer surface of the distal end of the cylindrical body is formed in the second section to be inclined toward the longitudinal axis of the cylindrical body toward the distal side, and in the first section to be inclined toward the longitudinal axis of the cylindrical body toward the distal side such that the angle between the outer surface and the longitudinal axis is greater than the angle between the outer surface and the longitudinal axis in the second section. The extension guide catheter according to any one of [1] to [3]. As described above, if the distal end of the tubular body is formed, it becomes easier to smoothly advance the distal end of the tubular body within the guide catheter or body cavity, and the distal end of the tubular body can bend and advance smoothly in curved sections of the guide catheter or body cavity.

[0011] [6] An extension guide catheter according to [4] or [5], wherein in the first section, the angle between the outer surface and the longitudinal axis is formed to increase gradually or continuously toward the distal side. As described above, if the distal end of the tubular body is formed, it becomes easier to smoothly advance the distal end of the tubular body through the guide catheter or within the body cavity.

[0012] [7] The groove is provided in the second section. [4] to [6] The extension guide catheter is as described above. As described above, if a groove is provided, a deeper groove can be formed at the distal end of the cylindrical body.

[0013] [8] The tubular body has a high-rigidity portion proximal to the distal end with respect to the longitudinal axis, and the high-rigidity portion is made of a material that is more rigid than the distal end. The extension guide catheter according to any one of [1] to [7]. If the tubular body is constructed as described above, it becomes easier to smoothly advance the tubular body through guide catheters and curved sections of body cavities.

[0014] [9] The distal end is composed of a resin layer, and the high-rigidity portion is composed of a resin layer and a helical, mesh-like, or braided reinforcing layer, as described in [8]. As described above, if the distal end of the cylindrical body is formed in this way, the lumen of the cylindrical body becomes less likely to collapse in the high-rigidity section, and kinking is less likely to occur. In addition, it becomes easier to insert a treatment device into the lumen of the cylindrical body.

[0015]

[10] An extension guide catheter according to any one of [1] to [9], wherein the distal end has an inner layer and an outer layer, the inner layer being made of a material with higher rigidity than the outer layer, and a groove is formed in at least the inner layer. If the distal end of the cylindrical body is constructed as described above, kinking will be less likely to occur at the distal end of the cylindrical body, and the flexibility of the distal end of the cylindrical body will be more easily ensured.

[0016]

[11] An extension guide catheter as described in any of [1] to

[10] , wherein the longitudinal length of the distal end is 1 mm or more and 10 mm or less. [Effects of the Invention]

[0017] The extended guide catheter of the present invention is provided with an annular or spiral groove portion extending in the circumferential direction on the inner side surface of the distal end portion of the tubular body, and the wall thickness of the tubular body is formed thin at the portion where the groove portion is provided. Therefore, it is easy to advance smoothly through the guide catheter and the body cavity, and even when the distal end portion of the tubular body is positioned at a bent portion of the body cavity, kinking is less likely to occur at the distal end portion of the tubular body, and the cross-sectional shape of the lumen at the relevant portion is less likely to be significantly distorted. As a result, it becomes easy to extend a treatment device such as an endovascular treatment instrument from the distal opening through the distal end portion of the tubular body. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] [Figure 1] The extended guide catheter according to the embodiment of the present invention is shown, representing the overall view of the extended guide catheter. [Figure 2] This represents a diagram showing a state in which the extended guide catheter according to the embodiment of the present invention is inserted into a guide catheter placed in a blood vessel and extended out from the distal opening of the guide catheter. [Figure 3] This represents an example of a cross-sectional view along the longitudinal axis direction of the distal end portion of the extended guide catheter according to the embodiment of the present invention. [Figure 4] This represents another example of a cross-sectional view along the longitudinal axis direction of the distal end portion of the extended guide catheter according to the embodiment of the present invention. [Figure 5] This represents another example of a cross-sectional view along the longitudinal axis direction of the distal end portion of the extended guide catheter according to the embodiment of the present invention. [Figure 6] This represents another example of a cross-sectional view along the longitudinal axis direction of the distal end portion of the extended guide catheter according to the embodiment of the present invention. [Figure 7] This represents another example of a cross-sectional view along the longitudinal axis direction of the distal end portion of the extended guide catheter according to the embodiment of the present invention. [Figure 8] This represents another example of a cross-sectional view along the longitudinal axis direction of the distal end portion of the extended guide catheter according to the embodiment of the present invention. [Figure 9]This shows another example of a cross-sectional view of the distal end of an extension guide catheter according to an embodiment of the present invention, along the longitudinal axis. [Figure 10] This shows another example of a cross-sectional view of the distal end of an extension guide catheter according to an embodiment of the present invention, along the longitudinal axis. [Figure 11] This shows another example of a cross-sectional view of the distal end of an extension guide catheter according to an embodiment of the present invention, along the longitudinal axis. [Figure 12] This shows another example of a cross-sectional view of the distal end of an extension guide catheter according to an embodiment of the present invention, along the longitudinal axis. [Figure 13] This shows another example of a cross-sectional view of the distal end of an extension guide catheter according to an embodiment of the present invention, along the longitudinal axis. [Modes for carrying out the invention]

[0019] The extension guide catheter of the present invention will be described in detail below based on the embodiments described below. However, the present invention is not limited by the embodiments described below, and it is certainly possible to implement it with appropriate modifications within the scope that is consistent with the spirit of the preceding and following descriptions, and all such modifications are included within the technical scope of the present invention. In addition, hatching and component reference numerals may be omitted in the drawings for convenience, in which case refer to the specification or other drawings. Furthermore, the dimensions of various components in the drawings may differ from the actual dimensions, as priority is given to helping to understand the features of the present invention.

[0020] An extension guide catheter according to an embodiment of the present invention will be described with reference to Figures 1 to 13. Figure 1 shows an overall view of an extension guide catheter according to an embodiment of the present invention, Figure 2 shows the extension guide catheter according to an embodiment of the present invention inserted into a guide catheter placed in a blood vessel and extended from the distal opening of the guide catheter, and Figures 3 to 13 show examples of cross-sectional views along the longitudinal axis of the distal end of an extension guide catheter according to an embodiment of the present invention.

[0021] An extension guide catheter is used in combination with a guide catheter. Specifically, it is inserted into the guide catheter and extended from the distal opening of the guide catheter. By using an extension guide catheter, treatment devices such as endovascular instruments can be delivered more stably to the distal end of the vascular system. Examples of endovascular instruments include stents and balloons.

[0022] As shown in Figure 1, the extension guide catheter 1 according to an embodiment of the present invention comprises a cylindrical body 2 having a lumen 3 extending in the longitudinal axis direction x, and a linear member 12 fixed to the cylindrical body 2 and extending proximal to the proximal opening 4 of the cylindrical body 2. The cylindrical body 2 has a proximal opening 4 and a distal opening 5. The proximal opening 4 of the cylindrical body 2 refers to the opening on the proximal side of the lumen 3 of the cylindrical body 2, and the distal opening 5 of the cylindrical body 2 refers to the opening on the distal side of the lumen 3 of the cylindrical body 2. In the cylindrical body 2, the portion including the distal end that forms the distal opening 5 is referred to as the distal end 6 of the cylindrical body 2. Specifically, in the cylindrical body 2, the range in the longitudinal axis direction x from the distal end of the cylindrical body 2 to the proximal end of the groove described later is referred to as the distal end 6 of the cylindrical body 2.

[0023] As shown in Figure 2, the extension guide catheter 1 is inserted into the guide catheter 21, which is already placed in the body cavity, during the procedure. Specifically, the extension guide catheter 1 is inserted into the guide catheter 21 through its proximal opening, and then extended distally through the distal opening 22 of the guide catheter 21. Figure 2 shows the extension guide catheter 1 positioned within the guide catheter 21, which is placed in the ascending aorta, with the extension guide catheter 1 extending from the distal opening 22 of the guide catheter 21.

[0024] The extension guide catheter 1 allows the tubular body 2 to be advanced or retracted within the guide catheter 21 by pushing or pulling the linear member 12, extending distally from the distal opening 22 of the guide catheter 21, or being retracted into the guide catheter 21. By sending treatment devices such as intravascular treatment instruments through the guide catheter 21 and the extension guide catheter 1, the treatment devices can be reached further into the body cavity. The inner diameter of the guide catheter 21 is larger than the outer diameter of the extension guide catheter 1 in order to accommodate the extension guide catheter 1. The treatment device can be extended distally from the distal opening 5 of the tubular body 2 of the extension guide catheter 1 by entering the guide catheter 21 through the proximal opening and passing through the guide catheter 21, and then entering the extension guide catheter 1 through the proximal opening 4 and passing through the extension guide catheter 1.

[0025] In the extension guide catheter 1, the longitudinal axis x is defined as the direction of extension of the extension guide catheter 1, specifically the direction of extension of the tubular body 2 and the linear member 12. The extension guide catheter 1 has a proximal side and a distal side, with respect to the longitudinal axis x. In the extension guide catheter 1, the proximal side refers to the direction toward the user, i.e., the operator's proximal side, with respect to the direction of extension of the extension guide catheter 1, and the distal side refers to the opposite direction of the proximal side, i.e., the direction toward the treatment target. The tubular body 2 has a radial direction, which is perpendicular to the longitudinal axis x. In Figure 1, the right side of the figure corresponds to the proximal side, and the left side of the figure corresponds to the distal side.

[0026] The length x in the longitudinal direction of the extension guide catheter 1 is preferably 800 mm or more, more preferably 1000 mm or more, even more preferably 1200 mm or more, preferably 2200 mm or less, more preferably 2000 mm or less, and even more preferably 1800 mm or less. The length x in the longitudinal direction of the cylindrical body 2 is preferably 100 mm or more, more preferably 200 mm or more, even more preferably 250 mm or more, preferably 600 mm or less, more preferably 500 mm or less, and even more preferably 450 mm or less.

[0027] From the viewpoint of ensuring the passability of the extension guide catheter 1 within the guide catheter and the passability of the treatment device within the extension guide catheter 1, the diameter of the lumen 3 of the cylindrical body 2 is preferably 1.0 mm or more, more preferably 1.1 mm or more, even more preferably 1.3 mm or more, preferably 2.2 mm or less, more preferably 2.0 mm or less, and even more preferably 1.9 mm or less. The outer diameter of the cylindrical body 2 is preferably 1.2 mm or more, more preferably 1.3 mm or more, even more preferably 1.4 mm or more, preferably 3.5 mm or less, more preferably 3.0 mm or less, and even more preferably 2.5 mm or less. The wall thickness of the cylindrical body 2 is preferably 0.01 mm or more, more preferably 0.02 mm or more, even more preferably 0.05 mm or more, preferably 0.4 mm or less, more preferably 0.3 mm or less, and even more preferably 0.2 mm or less.

[0028] In a cross-section perpendicular to the longitudinal axis x of the cylindrical body 2, the shape of the lumen 3 of the cylindrical body 2 and the shape of the outer edge of the cylindrical body 2 are not particularly limited and can be circular, elliptical, oblong, polygonal, irregular, etc. If the shape of the lumen 3 of the cylindrical body 2 or the shape of the outer edge of the cylindrical body 2 is other than circular, the diameter of the lumen 3 of the cylindrical body 2 and the outer diameter of the cylindrical body 2 described above mean the equivalent diameter of a circle. That is, it means the diameter of a circle with a circumference of the same length as the circumference of the lumen 3 of the cylindrical body 2 or the circumference of the outer edge of the cylindrical body 2. The shape of the lumen 3 of the cylindrical body 2 and the shape of the outer edge of the cylindrical body 2 are preferably circular or elliptical, and in the case of an ellipse, the ratio of the minor axis to the major axis is preferably 0.80 or more, more preferably 0.90 or more, and even more preferably 0.95 or more.

[0029] The cylindrical body 2 can be composed of, for example, a resin layer. Examples of resins that make up the resin layer include polyamide resin, polyester resin, polyurethane resin, polyolefin resin, fluororesin, vinyl chloride resin, silicone resin, and natural rubber. Examples of polyamide resins include nylon 12, nylon 12 elastomer, nylon 6, and aromatic polyamide. Examples of polyester resins include polyethylene terephthalate. Examples of polyurethane resins include aliphatic polyurethane containing aliphatic isocyanates as monomer units, and aromatic polyurethane containing aromatic isocyanates as monomer units. Examples of polyolefin resins include polyethylene and polypropylene. Examples of fluororesin include polytetrafluoroethylene, ethylenetetrafluoroethylene, and fluorinated ethylene propylene. Examples of vinyl chloride resins include polyvinyl chloride and polyvinylidene chloride. Examples of silicone resins include dimethylpolysiloxane, methylphenylpolysiloxane, methylvinylpolysiloxane, and fluoroalkylmethylpolysiloxane. Examples of natural rubber include latex.

[0030] The cylindrical body 2 may be composed of a single layer or multiple layers. Furthermore, in the longitudinal axis direction x, a part of the cylindrical body 2 may be composed of a single layer, while the other part is composed of multiple layers.

[0031] The cylindrical body 2 preferably has a reinforcing layer. The reinforcing layer can increase the rigidity of the cylindrical body 2. The reinforcing layer may be provided on the inner surface of the cylindrical body 2, on the outer surface, or between the inner and outer surfaces of the cylindrical body 2.

[0032] The reinforcing layer can be made of metal wires or fibers. Examples of materials for the metal wires include stainless steel, titanium, nickel-titanium alloy, cobalt-chromium alloy, and tungsten alloy. Stainless steel is preferred among these. The metal wire may be a single wire or a stranded wire. Examples of fibers include polyarylate fibers, aramid fibers, ultra-high molecular weight polyethylene fibers, PBO (poly(p-phenylenebenzoxazole)) fibers, and carbon fibers. The fibers may be monofilaments or multifilaments.

[0033] The shape of the reinforcing layer is not particularly limited, but helical, mesh-like, and braided shapes are preferred. Among these, a braided shape is more preferred because it can effectively increase the rigidity of the cylindrical body 2.

[0034] The cylindrical body 2 may contain a radiopaque material to facilitate its position under X-ray fluoroscopy. Examples of radiopaque materials include lead, barium, iodine, tungsten, gold, platinum, iridium, platinum-iridium alloy, stainless steel, titanium, cobalt-chromium alloy, palladium, and tantalum. For example, it is preferable to provide radiopaque markers at the proximal and distal ends of the cylindrical body 2, thereby allowing the position of the cylindrical body 2 within the body cavity to be confirmed under X-ray fluoroscopy.

[0035] The cylindrical body 2 may have its outer surface coated with a hydrophilic polymer. This facilitates the insertion of the cylindrical body 2 into a guide catheter or blood vessel. Examples of hydrophilic polymers include poly-2-hydroxyethyl methacrylate, polyacrylamide, polyvinylpyrrolidone, and maleic anhydride copolymers such as methyl vinyl ether maleic anhydride copolymer.

[0036] The cylindrical body 2 preferably has an inner layer and an outer layer. The inner layer and outer layer can be made of the resins described above. In particular, the inner layer is preferably made of at least one selected from the group consisting of polyester resin, polyolefin resin, fluororesin, silicone resin, and natural rubber. In particular, the inner layer is preferably made of a fluororesin because it has excellent chemical resistance, non-stick properties, and low friction. The outer layer is preferably made of at least one resin selected from the group consisting of polyamide resin, polyurethane resin, and polyolefin resin, more preferably made of at least one resin selected from the group consisting of polyamide resin and polyurethane resin, and even more preferably made of polyurethane resin.

[0037] The cylindrical body 2 preferably has a reinforcing layer in addition to the inner layer and outer layer. The reinforcing layer may be provided on the outer layer, on the inner layer, or between the inner and outer layers, but it is preferable that the reinforcing layer be provided between the inner and outer layers because it is easy to increase the strength of the cylindrical body 2.

[0038] The linear member 12 is a long wire and is fixed to the proximal end of the cylindrical body 2. By pushing or pulling the linear member 12, the cylindrical body 2 can be moved forward or backward, thereby allowing the cylindrical body 2 to protrude from the distal opening of the guide catheter or to be pulled back into the guide catheter.

[0039] The linear member 12 is preferably made of metal. Examples of metals that make up the linear member 12 include stainless steel, titanium, nickel-titanium alloy, cobalt-chromium alloy, tungsten alloy, etc., with stainless steel being more preferred. The cross-sectional shape of the linear member 12 in the direction perpendicular to the longitudinal axis x is not particularly limited, and examples include squares, rectangles, trapezoids and other quadrilaterals, polygons other than quadrilaterals, circles, ellipses, oblongs, etc. Among these, the cross-sectional shape of the linear member 12 is preferably quadrilateral.

[0040] Preferably, the extension guide catheter 1 is provided with a gripping member 13 at the proximal end of the linear member 12. By grasping the gripping member 13 with their fingers, the practitioner can easily push or pull the extension guide catheter 1. Resin is a possible material for the gripping member 13, and examples of resins include polyolefin resins such as polyethylene and polypropylene.

[0041] The linear member 12 may be fixed to the inner surface of the cylindrical body 2, to the outer surface of the cylindrical body 2, or between the inner and outer surfaces of the cylindrical body 2. If the cylindrical body 2 has an inner layer and an outer layer, the linear member 12 may be fixed to the inner layer of the cylindrical body 2, to the outer layer, or between the inner and outer layers. The linear member 12 is fixed to one radial side of the cylindrical body 2.

[0042] Incidentally, the extension guide catheter 1 is used by being inserted into the guide catheter or body cavity. However, when the extension guide catheter 1 is set to a desired position within the body cavity to deliver the treatment device from the guide catheter through the extension guide catheter 1, the distal end 6 of the tubular body 2 may be located in a curved portion of the body cavity. In this case, the distal end 6 of the tubular body 2 bends along the curved portion of the body cavity. In areas where the body cavity is sharply curved, a kink may occur at the distal end 6 of the tubular body 2. As a result, there is a concern that the cross-sectional shape of the lumen 3 of the tubular body 2 may be distorted at the distal end 6, narrowing the size of the lumen 3.

[0043] Therefore, in the extension guide catheter 1 according to an embodiment of the present invention, as shown in Figure 3, an annular or helical groove 7 extending in the circumferential direction is provided on the inner surface of the distal end 6 of the cylindrical body 2, and the wall thickness of the cylindrical body 2 is formed to be thinner in the portion where the groove 7 is provided. Figure 3 shows an example of a cross-sectional view along the longitudinal axis x of the distal end 6 of the extension guide catheter shown in Figure 1, and shows an example in which an annular groove 7 extending in the circumferential direction is provided on the inner surface of the distal end 6 of the cylindrical body 2. By forming the distal end 6 of the cylindrical body 2 in this way, the distal end 6 of the extension guide catheter 1 becomes more flexible and easier to bend, making it easier to advance the extension guide catheter 1 smoothly through the guide catheter and body cavity. Furthermore, even if the distal end 6 of the cylindrical body 2 is located in a curved portion of the body cavity, it is less likely that a kink will occur at the distal end 6 of the cylindrical body 2 that would cause the lumen 3 to collapse, and the cross-sectional shape of the lumen 3 in that portion will not be greatly distorted. Therefore, it becomes easy to extend treatment devices such as endovascular treatment instruments through the distal end 6 of the cylindrical body 2 and out through the distal opening 5. Furthermore, because the distal end 6 of the cylindrical body 2 has a groove 7 on its inner surface, it is less likely that a protruding portion will form on the inner surface of the lumen 3 when it is bent, thus preventing the lumen 3 from narrowing. Therefore, it becomes easy to extend treatment devices through the distal end 6 of the cylindrical body 2 and out through the distal opening 5.

[0044] The distal end 6 of the cylindrical body 2, when viewed from the inner surface, has a portion with a groove 7 and a portion without a groove 7. The wall thickness of the cylindrical body 2 in the portion with a groove 7 is thinner than the wall thickness of the cylindrical body 2 in the portion adjacent to the groove 7 and without a groove 7. Therefore, the groove 7 is formed as a bottomed groove. Preferably, the inner surface of the distal end 6 of the cylindrical body 2 is formed flat in the portion without a groove 7, and recessed in the portion with a groove 7 compared to the flat portion without a groove 7.

[0045] The groove 7 is preferably formed within a range of 10 mm from the distal end of the cylindrical body 2 towards the proximal end. Specifically, the proximal end of the groove 7 is preferably located within 10 mm from the distal end of the cylindrical body 2, more preferably within 9 mm, and even more preferably within 8 mm. Therefore, the length x in the longitudinal direction of the distal end 6 of the cylindrical body 2 is preferably 10 mm or less, more preferably 9 mm or less, and even more preferably 8 mm or less. On the other hand, the proximal end of the groove 7 is preferably located at a distance of 1 mm or more from the distal end of the cylindrical body 2 towards the proximal end, more preferably 1.5 mm or more, and even more preferably 2 mm or more. Therefore, the length x in the longitudinal direction of the distal end 6 of the cylindrical body 2 is preferably 1 mm or more, more preferably 1.5 mm or more, and even more preferably 2 mm or more.

[0046] The width of the groove 7, that is, the length of the groove 7 with respect to the longitudinal axis x of the cylindrical body 2, is preferably 0.5 mm or more, more preferably 0.8 mm or more, preferably 3.0 mm or less, and more preferably 2.5 mm or less. The depth of the groove 7 is preferably 0.1 times or more the wall thickness of the cylindrical body 2, more preferably 0.2 times or more, preferably 0.8 times or less, and more preferably 0.7 times or less. If the groove 7 is formed in this way, even if the distal end 6 of the cylindrical body 2 is located in a curved part of the body cavity, kinking of the distal end 6 of the cylindrical body 2 becomes less likely to occur, and the distal end 6 of the cylindrical body 2 becomes easier to bend smoothly. Note that the wall thickness of the cylindrical body 2 described here refers to the wall thickness of the cylindrical body 2 in the part adjacent to the groove 7 where no groove 7 is provided, and refers to the average value of the wall thickness of the cylindrical body 2 in the part adjacent distally to the groove 7 and the wall thickness of the cylindrical body 2 in the part adjacent proximal to the groove 7.

[0047] The cross-sectional shape of the groove 7, that is, the cross-sectional shape of the groove 7 when the distal end 6 of the cylindrical body 2 is cut along the longitudinal axis x as shown in Figure 3, is not particularly limited. Figure 3 shows an example of groove 7 with an arc-shaped cross-section, but the cross-sectional shape of the groove 7 may be formed in a V-shape, for example, as shown in Figure 4. The cross-sectional shape of the groove 7 may also be U-shaped or a polygon with one side cut off (for example, a rectangle with one side cut off). Furthermore, as shown in Figure 5, the cross-sectional shape of the groove 7 may be an arc made up of a part of an ellipse.

[0048] In a cross-section along the longitudinal axis x of the distal end 6 of the cylindrical body 2, the angle between the proximal wall surface of the groove 7 and the longitudinal axis x, and the angle between the distal wall surface of the groove 7 and the longitudinal axis x, may be the same or different. Here, the angle between the proximal or distal wall surface of the groove 7 and the longitudinal axis x refers to the angular difference between the extending direction of the proximal or distal wall surface of the groove 7 and the longitudinal axis x in a cross-section along the longitudinal axis x of the distal end 6 of the cylindrical body 2, and takes a range of greater than 0° and less than or equal to 90°. If the wall surface of the groove 7 is formed in a curved shape in a cross-section along the longitudinal axis x, the extending direction of the wall surface of the groove 7 refers to the extending direction of the tangent to the wall surface, and the angle that takes the largest angular difference from the longitudinal axis x is taken as the angle between the wall surface of the groove 7 and the longitudinal axis x.

[0049] For example, as shown in Figure 3, the angle between the proximal wall surface of the groove 7 and the longitudinal axis x may be the same as the angle between the distal wall surface of the groove 7 and the longitudinal axis x. Alternatively, as shown in Figure 4, the angle between the proximal wall surface of the groove 7 and the longitudinal axis x may be larger than the angle between the distal wall surface of the groove 7 and the longitudinal axis x. Conversely, as shown in Figure 5, the angle between the proximal wall surface of the groove 7 and the longitudinal axis x may be smaller than the angle between the distal wall surface of the groove 7 and the longitudinal axis x. Furthermore, as shown in Figures 4 and 5, if the angle between the proximal wall surface of the groove 7 and the longitudinal axis x is different from the angle between the distal wall surface of the groove 7 and the longitudinal axis x, then even if the distal end 6 of the cylindrical body 2 is bent at a sharper angle, it will be easier to bend it smoothly, and the width of the groove 7 can be increased, thus making it easier to suppress the occurrence of kinks when the distal end 6 of the cylindrical body 2 is bent.

[0050] When the groove 7 is formed in an annular shape extending in the circumferential direction, the number of annular grooves 7 formed at the distal end 6 of the cylindrical body 2 may be one or two or more. On the other hand, the upper limit of the number of annular grooves 7 formed at the distal end 6 of the cylindrical body 2 is preferably eight or less, more preferably six or less, and even more preferably four or less. When multiple annular grooves 7 are provided, the widths of the multiple annular grooves 7 may be the same or different, and the depths of the multiple annular grooves 7 may be the same or different. It is preferable that each annular groove 7 is formed to continuously encircle the cylindrical body 2 in the circumferential direction.

[0051] Figures 6 to 8 show examples in which multiple annular grooves 7 are provided at the distal end 6 of the cylindrical body 2. In Figure 6, three grooves 7 of the same size are provided at the distal end 6 of the cylindrical body 2, aligned along the longitudinal axis x. In Figure 7, three grooves 7 are provided at the distal end 6 of the cylindrical body 2, aligned along the longitudinal axis x such that the size of the proximal grooves 7 is larger than the size of the distal grooves 7. In Figure 8, three grooves 7 are provided at the distal end 6 of the cylindrical body 2, aligned along the longitudinal axis x such that the size of the distal grooves 7 is larger than the size of the proximal grooves 7. Providing multiple annular grooves 7 at the distal end 6 of the cylindrical body 2 in this way makes it easier to bend the distal end 6 of the cylindrical body 2 more significantly. Furthermore, by adjusting the size of each groove 7 arranged along the longitudinal axis x, it becomes possible to arbitrarily set the curvature of the distal end 6 of the cylindrical body 2.

[0052] When the groove 7 is formed in a helical shape, it is preferable that the helical groove 7 is formed to make at least one turn around the circumferential direction of the cylindrical body 2. The upper limit of the number of turns of the helical groove 7 is preferably 8 turns or less, more preferably 6 turns or less, and even more preferably 4 turns or less. Furthermore, it is preferable that the groove 7 be provided in an annular shape extending in the circumferential direction, as this makes it easier to ensure the isotropy of the bending of the distal end 6 of the cylindrical body 2.

[0053] Preferably, the distal end 6 of the cylindrical body 2 has a flat outer surface in the longitudinal axis x range where the groove 7 is provided. That is, unlike the inner surface of the distal end 6 of the cylindrical body 2, it is preferable that no irregularities such as grooves 7 are formed on the outer surface. If the distal end 6 of the cylindrical body 2 is formed in this way, when advancing the extension guide catheter 1 through the guide catheter or body cavity, the distal end 6 of the cylindrical body 2 will not get caught on the guide catheter or the inner wall of the body cavity, making it easier to advance the extension guide catheter 1 smoothly through the guide catheter or body cavity.

[0054] The outer surface of the distal end 6, which is formed in a flat shape, may be formed parallel to the longitudinal axis x in a cross-section along the longitudinal axis x, or it may be formed at an angle. For example, as shown in Figures 9 to 11, the outer surface of the distal end 6 of the cylindrical body 2 may have an inclined portion 8 that is inclined toward the longitudinal axis side of the cylindrical body 2 (i.e., toward the central axis side of the cylindrical body 2) toward the distal side. Figures 9 to 11 show an example in which the inclined portion 8 is formed on the outer surface of the distal end 6 of the cylindrical body 2 in the embodiment shown in Figure 6, and the configuration of the groove portion 7 can be changed as desired. In this way, if an inclined portion 8 is formed on the outer surface of the distal end 6 of the cylindrical body 2, the distal end 6 of the cylindrical body 2 will be able to advance more smoothly in the guide catheter or body cavity. In addition, the distal end 6 of the cylindrical body 2 will be able to bend and advance more smoothly in the curved portion of the guide catheter or body cavity. The inclined portion 8 may be formed on only a part of the distal end 6 of the cylindrical body 2, or it may be formed on the whole. Furthermore, the inclined portion 8 may be formed to extend from the distal end 6 to the proximal side of the distal end 6. It is preferable that the outer surface of the distal end 6 of the cylindrical body 2 does not have a portion that slopes toward the longitudinal axis of the cylindrical body 2 toward the proximal side.

[0055] In one embodiment, as shown in Figure 9, the distal end 6 of the cylindrical body 2 has a first section 9 including the distal end of the cylindrical body 2 and a second section 10 proximal to the longitudinal axis x, and the outer surface of the distal end 6 of the cylindrical body 2 can be formed parallel to the longitudinal axis x in the second section 10 and inclined toward the longitudinal axis of the cylindrical body 2 toward the distal side in the first section 9. If the distal end 6 of the cylindrical body 2 is formed in this way, it becomes easier to smoothly advance the distal end 6 of the cylindrical body 2 within a guide catheter or body cavity, and the distal end 6 of the cylindrical body 2 can bend and advance smoothly in curved portions of the guide catheter or body cavity.

[0056] In another embodiment, as shown in Figure 10, the distal end 6 of the cylindrical body 2 has a first section 9 including the distal end of the cylindrical body 2 and a second section 10 proximal to the longitudinal axis x, and the outer surface of the distal end 6 of the cylindrical body 2 is formed to be inclined toward the longitudinal axis of the cylindrical body 2 toward the distal side in the second section 10, and the angle between the outer surface and the longitudinal axis x in the first section 9 is larger than the angle between the outer surface and the longitudinal axis x in the second section 10, so that it is inclined toward the longitudinal axis of the cylindrical body 2 toward the distal side. Even if the distal end 6 of the cylindrical body 2 is formed in this way, it is easier to smoothly advance the distal end 6 of the cylindrical body 2 in a guide catheter or body cavity, and the distal end 6 of the cylindrical body 2 is easier to bend and advance smoothly in the curved portion of the guide catheter or body cavity.

[0057] When a first section 9 and a second section 10 are provided at the distal end 6 of the cylindrical body 2, the first section 9, which includes the distal end of the cylindrical body 2, may be formed such that the angle between the outer surface and the longitudinal axis direction x increases gradually or continuously toward the distal end. An example of the distal end 6 of the cylindrical body 2 being formed in this way is shown in Figure 11. In Figure 11, the first section 9 of the distal end 6 of the cylindrical body 2 is formed such that the angle between the outer surface and the longitudinal axis direction x increases continuously toward the distal end. Specifically, in a cross-section along the longitudinal axis direction x of the distal end 6 of the cylindrical body 2, the angle between the tangent to the outer surface of the first section 9 of the distal end 6 of the cylindrical body 2 and the longitudinal axis direction x increases continuously toward the distal end. As shown in Figure 11, if the first section 9 is formed, the outer surface of the distal end of the cylindrical body 2 is formed in a rounded cross-section. That is, in the cross-section along the longitudinal axis x of the distal end 6 of the cylindrical body 2, the outer surface of the distal end of the cylindrical body 2 is formed with rounded corners, making it easier to smoothly advance the distal end 6 of the cylindrical body 2 within a guide catheter or body cavity. If the first section 9 of the distal end 6 of the cylindrical body 2 is formed such that the angle between the outer surface and the longitudinal axis x increases gradually toward the distal end, the outer surface of the distal end of the cylindrical body 2 is formed with chamfering, similarly making it easier to smoothly advance the distal end 6 of the cylindrical body 2 within a guide catheter or body cavity.

[0058] When a first section 9 and a second section 10 are provided at the distal end 6 of the cylindrical body 2, it is preferable that the groove 7 be provided in the second section 10. This allows for the formation of a deeper groove at the distal end 6 of the cylindrical body 2, making it easier for the distal end 6 of the cylindrical body 2 to bend smoothly at the groove 7 in the guide catheter or the curved portion of the body cavity. Therefore, even when the distal end 6 of the cylindrical body 2 is located in the curved portion of the body cavity, kinking of the distal end 6 of the cylindrical body 2 becomes less likely. In this case, the groove 7 does not need to be provided in the first section 9.

[0059] It is preferable that the distal end 6 of the cylindrical body 2 is made of a resin layer. This makes it easier to form a groove 7 on the inner surface of the distal end 6 of the cylindrical body 2. In addition, the flexibility of the distal end 6 of the cylindrical body 2 is ensured, making it easier to bend in guide catheters and curved portions of body cavities. For a description of the resin layer of the distal end 6 of the cylindrical body 2, please refer to the description of the resin layer of the cylindrical body 2 above. The portion of the cylindrical body 2 proximal to the groove 7 may also be made of a resin layer.

[0060] The distal end 6 of the cylindrical body 2 may be configured to have an inner layer 6A and an outer layer 6B, as shown in Figure 12. In this case, it is preferable that the inner layer 6A is made of a material with higher rigidity than the outer layer 6B, and that the groove portion 7 is formed in at least the inner layer 6A. With the distal end 6 of the cylindrical body 2 configured in this way, kinking is less likely to occur at the distal end 6 of the cylindrical body 2, and the flexibility of the distal end 6 of the cylindrical body 2 is more easily ensured. The inner layer 6A is preferably made of at least one selected from the group consisting of polyester resin, polyolefin resin, fluororesin, silicone resin, natural rubber, polyamide resin, and polyurethane resin. The outer layer 6B is preferably made of at least one resin selected from the group consisting of polyamide resin, polyurethane resin, and polyolefin resin, more preferably made of at least one resin selected from the group consisting of polyamide resin and polyurethane resin, and even more preferably made of polyurethane resin.

[0061] As shown in Figures 12 and 13, it is preferable that the cylindrical body 2 has a high-rigidity portion 11 proximal to the distal end 6 with respect to the longitudinal axis x, and that the high-rigidity portion 11 is made of a material with higher rigidity than the distal end 6. With the cylindrical body 2 configured in this way, it becomes easier to smoothly advance the cylindrical body 2 in the guide catheter and the curved portion of the body cavity. Note that Figures 12 and 13 show examples in the embodiment shown in Figure 6 in which the distal end 6 of the cylindrical body 2 is configured to have an inner layer 6A and an outer layer 6B, and an example in which the high-rigidity portion 11 is formed proximal to the distal end 6, but the configuration of the groove portion 7 and the configuration of the outer surface of the cylindrical body 2 can be changed as desired.

[0062] The high-rigidity section 11 is preferably composed of a resin layer 11A and a helical, mesh-like, or braided reinforcing layer 11B, as shown in Figure 13. The reinforcing layer 11B can be formed by arranging metal wires or fibers in a helical, mesh-like, or braided manner. By providing the reinforcing layer 11B to the high-rigidity section 11 in this way, the lumen 3 of the cylindrical body 2 becomes less likely to collapse in the high-rigidity section 11, and kinking is less likely to occur. In addition, it becomes easier to insert a treatment device into the lumen 3 of the cylindrical body 2. The resin layer 11A of the high-rigidity section 11 may be composed of the same resin as the resin layer of the distal end 6 of the cylindrical body 2, or it may be composed of a different resin. Furthermore, the resin layer 11A of the high-rigidity section 11 may be configured to have an inner layer and an outer layer.

[0063] When a high-rigidity portion 11 is provided on the cylindrical body 2, the distal end of the high-rigidity portion 11 is preferably located within 15 mm proximal to the distal end of the cylindrical body 2, more preferably within 12 mm, and even more preferably within 10 mm. As described above, the high-rigidity portion 11 is provided so as to be located proximal to the distal end 6 where the groove portion 7 is provided. The proximal end of the high-rigidity portion 11 is preferably located within 15 mm distal to the proximal end of the cylindrical portion of the cylindrical body 2, more preferably within 12 mm, and even more preferably within 10 mm.

[0064] In the cylindrical body 2, it is preferable that a reinforcing layer is not provided at the distal end 6 where the groove 7 is located. This ensures the flexibility of the distal end 6 of the cylindrical body 2, thereby improving the flexibility of the guide catheter and the curved portion of the body cavity.

[0065] This application claims the benefit of priority based on Japanese Patent Application No. 2021-169117, filed on 14 October 2021. The entire specification of Japanese Patent Application No. 2021-169117, filed on 14 October 2021, is incorporated herein by reference. [Explanation of symbols]

[0066] 1: Extension guide catheter 2: Cylindrical body 3: Lumen 4: Proximal opening 5: Distal opening 6: Distal end, 6A: Inner layer, 6B: Outer layer 7: Groove 8: Inclined part 9: Section 1 10: Section 2 11: High rigidity part, 11A: Resin layer, 11B: Reinforcement layer 12: Linear member 13: Gripping member 21: Guide catheter

Claims

1. An extension guide catheter for a guide catheter, A cylindrical body having a lumen extending in the longitudinal direction and having a proximal opening and a distal opening, It has a linear member that is fixed to the cylindrical body and extends proximal to the proximal opening of the cylindrical body, The distal end of the cylindrical body is made of resin. The distal end of the cylindrical body has a first section including the distal end of the cylindrical body and a second section proximal to the distal end with respect to the longitudinal axis. The outer surface of the distal end of the cylindrical body is formed parallel to the longitudinal axis in the second section and inclined toward the longitudinal axis of the cylindrical body toward the distal end in the first section. An extension guide catheter having a circumferentially extending annular or helical groove on the inner surface of the second section of the distal end, wherein the wall thickness of the cylindrical body is formed to be thinner in the portion where the groove is provided.

2. An extension guide catheter for a guide catheter, A cylindrical body having a lumen extending in the longitudinal direction and having a proximal opening and a distal opening, It has a linear member that is fixed to the cylindrical body and extends proximal to the proximal opening of the cylindrical body, The distal end of the cylindrical body is made of resin. The distal end of the cylindrical body has a first section including the distal end of the cylindrical body and a second section proximal to the distal end with respect to the longitudinal axis. The outer surface of the distal end of the cylindrical body is formed in the second section to be inclined toward the longitudinal axis of the cylindrical body toward the distal side, and in the first section to be inclined toward the longitudinal axis of the cylindrical body toward the distal side such that the angle between the outer surface and the longitudinal axis is greater than the angle between the outer surface and the longitudinal axis in the second section. An extension guide catheter having a circumferentially extending annular or helical groove on the inner surface of the second section of the distal end, wherein the wall thickness of the cylindrical body is formed to be thinner in the portion where the groove is provided.

3. The extension guide catheter according to claim 1 or 2, wherein the distal end of the cylindrical body has a flat outer surface in the longitudinal axis region in which the groove is provided.

4. The extension guide catheter according to claim 1 or 2, wherein, in the first section, the angle between the outer surface and the longitudinal axis increases gradually or continuously toward the distal side.

5. The extension guide catheter according to claim 1 or 2, wherein the cylindrical body has a high-rigidity portion proximal to the distal end with respect to the longitudinal axis, and the high-rigidity portion is made of a material that is more rigid than the distal end.

6. The extension guide catheter according to claim 5, wherein the distal end is composed of a resin layer, and the high-rigidity portion is composed of a resin layer and a helical, mesh-like, or braided reinforcing layer.

7. The extension guide catheter according to claim 1 or 2, wherein the distal end has an inner layer and an outer layer, the inner layer is made of a material with higher rigidity than the outer layer, and the groove is formed in at least the inner layer.

8. The extension guide catheter according to claim 1 or 2, wherein the length of the distal end in the longitudinal direction is 1 mm or more and 10 mm or less.

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