Extension guide catheter

Abstract

Provided is an extension guide catheter which is for a guide catheter and which comprises a tubular body (2) having an inner cavity (4) that extends in the lengthwise axis direction and a wire-like member (10) extending to the proximal side from the tubular body (2), wherein: the tubular body (2) has a tubular portion (3) and a non-tubular proximal extending portion that extends to the proximal side from the tubular portion (3); the proximal extending portion has an inclined part; and the inner cavity (4) of the tubular body (2) at the proximal end of the tubular portion (3) has a shape that satisfies the following requirement. [Requirement] In a cross-section of the inner cavity (4) perpendicular to the lengthwise axis direction, when L1 is defined as the length of a first imaginary line segment where a first imaginary line (V1) that passes through the wire-like member (10) and extends in the vertical direction overlaps with the inner cavity (4), and L2 is defined as the length of a second imaginary line segment where a second imaginary line (V2) that passes through the center point of the first imaginary line segment and that extends perpendicularly to the first imaginary line (V1) overlaps with the inner cavity (4), L1 is longer than L2.

Description

TECHNICAL FIELD

[0001] The present invention relates to an extended guide catheter for a guide catheter, and more particularly, to an extended 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 and indwelled at the entrance of the coronary artery, the intravascular treatment instrument is delivered through the guide catheter, so that the insertability of the intravascular treatment instrument to 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 be dislodged from the entrance of the coronary artery. In that case, an extended guide catheter having a smaller diameter than the guide catheter may be inserted into the guide catheter to protrude the extended guide catheter from the distal opening of the guide catheter, thereby improving the backup force.

[0003] Various such extended 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 in which a groove is formed and a second surface on the opposite side thereof, and a distal shaft having a passage adjacent to the push member. Patent Document 3 discloses an extended 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 delivering treatment devices such as intravascular treatment instruments from the guide catheter through the extension guide catheter, the extension guide catheter may be located in a body cavity or a bent portion of the guide catheter. In this case, there is a concern that it may become difficult to insert treatment devices such as intravascular treatment instruments into the extension guide catheter in the body cavity or the bent portion of the 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 facilitates the insertion of treatment devices such as intravascular treatment instruments. [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 tubular body having a lumen extending in the longitudinal direction and having a proximal opening and a distal opening; a linear member fixed to the tubular body and extending proximal to the proximal opening of the tubular body, wherein the tubular body has an upper side to which the linear member is fixed and a lower side opposite to the upper side with respect to the radial direction; the tubular body has a tubular portion and a non-tubular proximal extension portion extending proximal to the tubular portion, the proximal opening is formed in the proximal extension portion, the proximal extension portion has an inclined portion that slopes distally from the upper side to the lower side; and the lumen of the tubular body has a shape that satisfies the following requirements at the proximal end of the tubular portion. [Requirement] In a vertical cross-section of the lumen in the longitudinal axis direction, let L1 be the length of the portion where a first imaginary line passing through the linear member and extending vertically overlaps the lumen (hereinafter referred to as the "first imaginary line segment"), and let L2 be the length of the portion where a second imaginary line passing through the midpoint of the first imaginary line segment and extending perpendicularly to the first imaginary line overlaps the lumen (hereinafter referred to as the "second imaginary line segment"), then L1 is longer than L2.

[0007] The extension guide catheter of the present invention is provided with a proximal extension portion having an inclined section. When the proximal end of the tubular body is located in a body cavity or in a bent portion of the guide catheter, the bending force applied to the proximal extension portion is transmitted to the tubular body, allowing the tubular body to bend smoothly from its proximal end or deform vertically. In this case, the tubular body is formed such that the cross-sectional shape of the lumen at the proximal end of the tubular body is such that L1 is longer than L2, i.e., it is elongated vertically. This makes it less likely for the lumen of the tubular body to collapse significantly vertically, making it easier to insert a treatment device into the lumen of the tubular body. Moreover, by bending the proximal end of the tubular body, the cross-sectional shape of the lumen at the proximal end of the tubular body can be such that the vertical length and the width are approximately equal. In this case, it becomes even easier to insert a treatment device into the lumen of the tubular body.

[0008] [2] The extension guide catheter described in [1] wherein L1 is 1.02 times or more and 1.50 times longer than L2. As described above, if a lumen is formed at the proximal end of the tubular portion, the effects of the present invention will be more reliably achieved.

[0009] [3] The extension guide catheter according to [1] or [2], wherein the inclined portion is inclined distally from the top to the bottom, forming an angle of 5° to 60° with respect to the longitudinal axis in a plan view formed from the longitudinal axis direction and the top and bottom direction of the cylindrical body. As described above, if an inclined section is formed, the proximal extension of the tubular body will be able to bend more smoothly when the proximal end is located in a body cavity or a curved section of a guide catheter.

[0010] [4] The extension guide catheter described in any of [1] to [3], wherein the proximal end of the tubular portion is formed such that the wall thickness of the upper and lower portions of the tubular body is greater than the wall thickness of the portion in between. As described above, if the proximal end of the tubular portion is formed, it becomes easier to ensure vertical flexibility at the proximal end of the tubular portion, making it easier to smoothly move the extension guide catheter along the longitudinal axis in the body cavity or the bent portion of the guide catheter.

[0011] [5] The extension guide catheter according to any one of [1] to [4], wherein the linear member extends distally from the distal end of the proximal opening and is fixed to the tubular portion and the proximal extension portion. As described above, if a linear member is provided, when a bending force is applied to the proximal portion of the cylindrical body, the cylindrical body will bend more smoothly from the proximal extension to the cylindrical portion, making it less likely for the cylindrical portion to bend irregularly or for kinks to form in the cylindrical portion. [Effects of the Invention]

[0012] In the extension guide catheter of the present invention, when the proximal end of the tubular body is positioned in a body cavity or a bent portion of the guide catheter, the bending force applied to the proximal extension is transmitted to the tubular body, allowing the tubular body to smoothly bend from its proximal end or deform vertically. Furthermore, since the cross-sectional shape of the lumen at the proximal end of the tubular body is formed to be elongated vertically, the vertical collapse of the lumen of the tubular body is suppressed, making it easier to insert a treatment device into the lumen of the tubular body. [Brief explanation of the drawing]

[0013] [Figure 1] This diagram shows an extension guide catheter according to an embodiment of the present invention, and represents an overall view of the extension guide catheter. [Figure 2] Figure 1 shows a side view of the proximal end of the tubular body of the extension guide catheter. [Figure 3] This figure shows an extension guide catheter according to an embodiment of the present invention, inserted into a guide catheter placed in a blood vessel, and extending from the distal opening of the guide catheter. [Figure 4] Figure 2 shows an example of an IV-IV cross-sectional view of the tubular body of the extension guide catheter. [Figure 5] Figure 2 shows another example of an IV-IV cross-sectional view of the tubular body of the extension guide catheter. [Modes for carrying out the invention]

[0014] 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.

[0015] With reference to FIG. 1 to FIG. 5, the extended guide catheter according to the embodiment of the present invention will be described. FIG. 1 is an overall view of the extended guide catheter according to the embodiment of the present invention, FIG. 2 is a side view of the proximal end portion of the tubular body of the extended guide catheter shown in FIG. 1, FIG. 3 is a view 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, and FIG. 4 and FIG. 5 are IV-IV cross-sectional views of the tubular body of the extended guide catheter shown in FIG. 2.

[0016] The extended guide catheter is used in combination with a guide catheter, and specifically, is used by being inserted into the guide catheter and extended out from the distal opening of the guide catheter. By using the extended guide catheter, treatment devices such as endovascular therapeutic instruments can be stably delivered to more peripheral sites. Examples of the endovascular therapeutic instrument include stents, balloons, and the like.

[0017] As shown in FIG. 1 and FIG. 2, the extended guide catheter 1 according to the embodiment of the present invention includes a tubular body 2 having a lumen 4 extending in the longitudinal axis direction x, and a linear member 10 fixed to the tubular body 2 and extending to the proximal side beyond the proximal opening 5 of the tubular body 2.

[0018] As shown in FIG. 3, during a medical procedure, the extended guide catheter 1 is used by being inserted into a guide catheter 21 that has been placed in a body cavity in advance. Specifically, the extended guide catheter 1 is inserted into the guide catheter 21 from the proximal opening of the guide catheter 21, and is used by extending the extended guide catheter 1 distally from the distal opening 22 of the guide catheter 21. FIG. 3 shows a state in which the extended guide catheter 1 is disposed inside the guide catheter 21 placed in the ascending aorta, and the extended guide catheter 1 extends out from the distal opening 22 of the guide catheter 21.

[0019] 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 10, 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 6 of the tubular body 2 of the extension guide catheter 1 by entering the guide catheter 21 through its proximal opening and passing through the guide catheter 21, and then entering the extension guide catheter 1 through its proximal opening 5 and passing through the extension guide catheter 1.

[0020] 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 10. 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.

[0021] 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.

[0022] The cylindrical body 2 can be made of, for example, a resin. Examples of resins include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, fluoropolymer resins, vinyl chloride resins, silicone resins, and natural rubber. Examples of polyamide resins include nylon 12, nylon 12 elastomer, nylon 6, and aromatic polyamides. Examples of polyester resins include polyethylene terephthalate. Examples of polyurethane resins include aliphatic polyurethanes containing aliphatic isocyanates as monomer units, and aromatic polyurethanes containing aromatic isocyanates as monomer units. Examples of polyolefin resins include polyethylene and polypropylene. Examples of fluoropolymer resins 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] The linear member 10 is a long wire and is fixed to the proximal end of the cylindrical body 2. By pushing or pulling the linear member 10, 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.

[0032] The linear member 10 is preferably made of metal. Examples of metals that make up the linear member 10 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 10 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 10 is preferably quadrilateral.

[0033] Preferably, the extension guide catheter 1 is provided with a gripping member 11 at the proximal end of the linear member 10. By grasping the gripping member 11 with their fingers, the practitioner can easily push or pull the extension guide catheter 1. Resin is a possible material for the gripping member 11, and examples of resins include polyolefin resins such as polyethylene and polypropylene.

[0034] The linear member 10 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 10 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 10 is fixed to one side of the cylindrical body 2 in the radial direction, and the cylindrical body 2 is defined as having an upper side on which the linear member 10 is fixed and an lower side on the opposite side in the radial direction. That is, the cylindrical body 2 has an upper side on which the linear member 10 is fixed and an lower side on the opposite side in the radial direction. Furthermore, the direction extending from the upper side to the lower side in the radial direction is called the vertical direction, and the direction perpendicular to it is called the width direction. The vertical direction is more specifically defined as a straight line that passes through the centroid of the linear member 10 and also through the centroid of the cross-sectional shape of the lumen 4 in a vertical cross-section in the longitudinal axis direction x of the lumen 4 of the cylindrical body 2.

[0035] The cylindrical body 2 has a proximal opening 5 and a distal opening 6. The proximal opening 5 of the cylindrical body 2 refers to the proximal opening of the lumen 4 of the cylindrical body 2, and the distal opening 6 of the cylindrical body 2 refers to the distal opening of the lumen 4 of the cylindrical body 2. The proximal opening 5 of the cylindrical body 2 has a portion that is inclined with respect to the longitudinal axis x. The cylindrical body 2 has a cylindrical portion 3 formed in a cylindrical shape and a non-cylindrical proximal extension portion 7 that extends proximal to the cylindrical portion 3, and the proximal opening 5 is formed in the proximal extension portion 7. The lumen 4 of the cylindrical body 2 is formed in the cylindrical portion 3.

[0036] The proximal extension portion 7 has an inclined portion 8 that slopes distally from the top to the bottom. In the cylindrical body 2, the proximal extension portion 7 in which the outer edge of the proximal opening 5 is formed, specifically the portion of the proximal extension portion 7 that includes the inclined portion 8, and the portion adjacent to it distally, are referred to as the proximal end of the cylindrical body 2. For example, the portion of the proximal extension portion 7 that includes the inclined portion 8, and the portion within 20 mm distal to the proximal end of the adjacent cylindrical portion 3, can be considered the proximal end of the cylindrical body 2. Also, the portion within 5 mm distal to the proximal end of the cylindrical portion 3 is referred to as the proximal end of the cylindrical portion 3.

[0037] The inclined portion 8 is formed such that the outer edge of the proximal opening 5 formed in the proximal extension portion 7 is inclined distally from the top to the bottom. In the extension guide catheter 1 according to the embodiment of the present invention, by providing the proximal extension portion 7 having the inclined portion 8 in this way, when the proximal end of the tubular body 2 is located in a curved portion of a body cavity such as a blood vessel or in a curved portion of the guide catheter, irregular bending of the tubular body 2 at the tubular portion 3 or kinking of the tubular portion 3 is suppressed. To explain this in more detail, the extension guide catheter 1 is used by being inserted into the guide catheter and body cavity, but when a treatment device is sent from the guide catheter through the extension guide catheter 1, the proximal end of the tubular body 2 may be located in a curved portion of the body cavity or the guide catheter when the extension guide catheter 1 is set in a desired position in the body cavity. In this case, the proximal end of the tubular body 2 bends along the curved portion of the body cavity or guide catheter, with the lower side of the tubular body 2 facing inward. However, because the tubular body 2 has a proximal extension portion 7, the proximal extension portion 7 bends before the tubular body 3, and the bending force applied to the proximal extension portion 7 is transmitted to the tubular body 3. As a result, the tubular body 3 can bend smoothly from its proximal end and deform vertically. In contrast, if the tubular body 2 does not have a proximal extension portion 7, the tubular body 2 bends first at the tubular body 3, causing the tubular body 3 to bend irregularly or to be prone to kinking.

[0038] Incidentally, when a bending force from the proximal extension portion 7 is transmitted to the tubular portion 3, the lumen 4 of the tubular body 2 deforms so as to collapse vertically at the proximal end of the tubular portion 3. In this case, if the lumen 4 of the tubular body 2 collapses significantly vertically, it may become difficult to insert a treatment device such as an endovascular treatment instrument into the lumen of the tubular body 2 through the proximal opening 5 of the tubular body 2. Therefore, in the extension guide catheter 1 according to an embodiment of the present invention, the cross-sectional shape of the lumen 4 of the tubular body 2 at the proximal end of the tubular portion 3 is formed to be elongated vertically. Specifically, at the proximal end of the tubular portion 3, the lumen 4 of the tubular body 2 is formed as follows. In other words, as shown in Figures 4 and 5, in a vertical cross-section of the lumen 4 of the cylindrical body 2 in the longitudinal axis direction x, the length of the portion where a first imaginary line V1 extending vertically through the linear member 10 overlaps with the lumen 4 (hereinafter referred to as the "first imaginary line segment") is L1, and the length of the portion where a second imaginary line V2 passing through the midpoint of the first imaginary line segment and extending perpendicularly to the first imaginary line V1 overlaps with the lumen 4 (hereinafter referred to as the "second imaginary line segment") is L2, is formed such that L1 is longer than L2. The first imaginary line V1 is defined as a straight line that passes through the centroid of the linear member 10 and also passes through the centroid of the cross-sectional shape of the lumen 4 in a vertical cross-section of the lumen 4 of the cylindrical body 2 in the longitudinal axis direction x, and the direction in which the first imaginary line V1 extends is defined as the vertical direction. The length L1 of the first imaginary line segment is the vertical length of the cross-sectional shape of the lumen 4 at the proximal end of the cylindrical portion 3, and the length L2 of the second imaginary line segment is the widthwise length of the cross-sectional shape of the lumen 4 at the proximal end of the cylindrical portion 3. If the lumen 4 of the cylindrical body 2 is formed in this way at the proximal end of the cylindrical portion 3, even if the proximal end of the cylindrical body 2 is bent, the lumen 4 of the cylindrical body 2 at the proximal end of the cylindrical portion 3 will not be greatly crushed vertically, making it easier to insert the treatment device into the lumen 4 of the cylindrical body 2. Rather, by bending the proximal end of the cylindrical body 2, the cross-sectional shape of the lumen 4 at the proximal end of the cylindrical portion 3 may have approximately equal vertical and widthwise lengths, in which case it becomes even easier to insert the treatment device into the lumen 4 of the cylindrical body 2.

[0039] The cross-sectional shape of the lumen 4 at the proximal end of the cylindrical portion 3 can be determined based on the shape of the lumen 4 at a point 1 mm distal to the proximal end of the cylindrical portion 3. That is, by cutting the cylindrical body 2 perpendicular to the longitudinal axis x at a point 1 mm distal to the proximal end of the cylindrical portion 3 and observing the resulting cross-sectional shape, the lengths of the first virtual line segment L1 and the second virtual line segment L2 of the vertical cross-section of the lumen 4 at the proximal end of the cylindrical portion 3 can be determined.

[0040] Regarding the cross-sectional shape of the lumen 4 at the proximal end of the cylindrical portion 3, the length L1 of the first imaginary line segment is preferably 1.02 times or longer than the length L2 of the second imaginary line segment, more preferably 1.04 times or longer, preferably 1.50 times or less, more preferably 1.40 times or less, and even more preferably 1.30 times or less. In other words, the cross-sectional shape of the lumen 4 at the proximal end of the cylindrical portion 3 is preferably such that the ratio L1 / L2 is 1.02 or more, more preferably 1.04 or more, preferably 1.50 or less, more preferably 1.40 or less, and even more preferably 1.30 or less. If the lumen 4 at the proximal end of the cylindrical portion 3 is formed in this manner, the above effects will be more reliably achieved.

[0041] The cross-sectional shape of the lumen 4 at the proximal end of the cylindrical portion 3 is not particularly limited as long as it is formed to be long in the vertical direction, and examples include elliptical, oblong, egg-shaped, polygonal, and irregular shapes. Preferably, the cross-sectional shape of the lumen 4 at the proximal end of the cylindrical portion 3 is formed symmetrically in the width direction, which makes it easier to insert the treatment device into the lumen 4 of the cylindrical body 2. Forming symmetrically in the width direction means forming symmetrically with respect to a plane defined by the longitudinal axis x and the vertical direction. On the other hand, the cross-sectional shape of the lumen 4 at the proximal end of the cylindrical portion 3 may or may not be formed symmetrically in the vertical direction. For example, the cross-sectional shape of the lumen 4 at the proximal end of the cylindrical portion 3 may be egg-shaped, trapezoidal, or kite-shaped. The cross-sectional shape of the lumen 4 at the proximal end of the cylindrical portion 3 is preferably such that the maximum length in the width direction is less than or equal to the length in the vertical direction (i.e., the length L1 of the first imaginary line segment), thereby making it less likely for the lumen 4 at the proximal end of the cylindrical portion 3 to collapse significantly in the vertical direction. The cross-sectional shape of the lumen 4 at the proximal end of the cylindrical portion 3 is preferably formed as an ellipse or oblong shape. An oblong shape means a shape like a running track, where two semicircles are connected by two parallel lines of equal length.

[0042] The cylindrical portion 3 may have a vertically elongated cross-sectional shape of the lumen 4 even in portions other than the proximal end. For example, the cylindrical portion 3 may have a vertically elongated cross-sectional shape of the lumen 4 along its entire length in the longitudinal axis x. However, in portions of the cylindrical portion 3 away from the proximal end, for example, portions 30 mm or more distal to the proximal end of the cylindrical portion 3, it is preferable that the vertical length of the cross-sectional shape of the lumen 4 of the cylindrical body 2 is closer to the width length. For example, it is preferable that the ratio L1 / L2 of the cross-sectional shapes of the lumen 4 in portions of the cylindrical portion 3 away from the proximal end is smaller than the ratio L1 / L2 of the cross-sectional shapes of the lumen 4 at the proximal end of the cylindrical portion 3, and larger than the ratio L2 / L1 of the cross-sectional shapes of the lumen 4 at the proximal end of the cylindrical portion 3. Furthermore, the ratio L1 / L2 of the cross-sectional shape of the lumen 4 in the portion of the cylindrical portion 3 away from the proximal end is preferably greater than 0.95 and less than 1.05, and more preferably between 0.97 and 1.03. The formation of the cylindrical portion 3 in this manner makes it easier to move the treatment device in the longitudinal axis direction x within the lumen 4 of the cylindrical body 2. The cross-sectional shape of the lumen 4 in the portion of the cylindrical portion 3 away from the proximal end can be determined, for example, based on the shape of the lumen 4 at points 30 mm and 100 mm distal to the proximal end of the cylindrical portion 3.

[0043] The equivalent circular diameter of the lumen 4 of the cylindrical body 2 at the proximal end of the cylindrical portion 3 is preferably 1.0 mm or more, more preferably 1.2 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, from the viewpoint of ensuring the insertion of the treatment device within the extension guide catheter 1. The equivalent circular diameter refers to the diameter of a circle with a circumference equal to the circumference of the lumen 4 of the cylindrical body 2. It is preferable that the diameter or equivalent circular diameter of the lumen 4 of the cylindrical body 2 is within this range even in parts other than the proximal end of the cylindrical portion 3.

[0044] The outer diameter of the cylindrical body 2 at the proximal end of the cylindrical portion 3 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, from the viewpoint of ensuring the insertion of the extension guide catheter 1 into the guide catheter. 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. The outer diameter of the cylindrical body 2 described here means the equivalent diameter of a circle, which means the diameter of a circle with a circumference of the same length as the circumference of the outer diameter of the cylindrical body 2. It is preferable that the outer diameter and wall thickness of the cylindrical body 2 are within this range even in parts other than the proximal end of the cylindrical portion 3.

[0045] The wall thickness of the cylindrical body 2 may be uniform in the circumferential direction of the cylindrical portion 3, or it may be thicker or thinner in some parts of the circumferential direction of the cylindrical portion 3. For example, as shown in Figure 5, it is preferable that at the proximal end of the cylindrical portion 3, the wall thickness of the upper and lower parts of the cylindrical body 2 is thicker than the wall thickness of the part in between. If the proximal end of the cylindrical portion 3 is formed in this way, it becomes easier to ensure flexibility in the vertical direction at the proximal end of the cylindrical portion 3, making it easier to smoothly move the extension guide catheter 1 in the longitudinal axis direction x in the body cavity or the bent part of the guide catheter. Note that the upper and lower parts of the cylindrical body 2 refer to the upper 1 / 4 and lower 1 / 4 portions of the cylindrical body 2, respectively, in a side view of the cylindrical body 2, that is, in a plan view formed from the longitudinal axis direction x and the vertical direction of the cylindrical body 2. Furthermore, the statement that the wall thickness of the upper and lower portions of the cylindrical body 2 is greater than the wall thickness of the portion in between means that the entire upper and lower portions of the cylindrical body 2 are thicker than the portion in between, i.e., the middle portion of the cylindrical body 2. In this case, the maximum wall thickness of the upper and lower portions of the cylindrical body 2 is preferably 1.1 times or more, more preferably 1.2 times or more, preferably 3.0 times or less, more preferably 2.5 times or less, and even more preferably 2.0 times or less.

[0046] As described above, the proximal extension portion 7 of the cylindrical body 2 has an inclined portion 8 that slopes distally from the top to the bottom. The inclined portion 8 of the proximal extension portion 7 is formed to extend distally from the top to the bottom in a side view of the cylindrical body 2, that is, in a plan view formed from the longitudinal axis x of the cylindrical body 2 and the top and bottom directions. The inclined portion 8 may be formed in a straight line, a curved line, or a combination of these shapes.

[0047] Preferably, the inclined portion 8 is formed to extend distally from the top to the bottom, inclined at an angle of 5° to 60° with respect to the longitudinal axis x when viewed from the side of the cylindrical body 2. The angle is preferably 10° or more, more preferably 12° or more, and preferably 50° or less. When the inclined portion 8 is formed in this way, the proximal extension portion 7 bends smoothly when the proximal end of the cylindrical body 2 is located in a body cavity or a curved portion of a guide catheter. The upper limit of the angle of the inclined portion 8 may be greater than 60°, for example, 80° or less or 70° or less, and it may also be less than 50°, for example, 40° or less or 30° or less. The angle described here refers to the angle between the direction of extension of the outer edge of the proximal extension portion 7 in the inclined portion 8 and the longitudinal axis x when viewed from the side of the cylindrical body 2. The extension direction of the outer edge of the proximal extension portion 7 in the inclined portion 8 means the extension direction of the straight line if the inclined portion 8 is formed in a straight line, and means the extension direction of the tangent to the curve if the inclined portion 8 is formed in a curved shape. The inclined portion 8 includes a first inclined portion and a second inclined portion, and in a side view of the cylindrical body 2, the angles made between the first inclined portion and the second inclined portion and the longitudinal axis direction x may be different from each other.

[0048] In the proximal extension portion 7, it is preferable that the inclined portion 8 is formed in at least a part of the lower two-thirds of the cylindrical body 2 in a side view of the cylindrical body 2, that is, in at least a part of the portion below the lower end of the upper one-third of the cylindrical body 2. In the proximal extension portion 7, the inclined portion 8 may be formed over, for example, the entire lower half of the cylindrical body 2, or over the entire lower two-thirds of the cylindrical body 2. In addition to the inclined portion 8, the proximal extension portion 7 may also have a portion in a side view of the cylindrical body 2 where the outer edge of the proximal opening 5 is convex upward, and this portion may be formed distal to the inclined portion 8. Furthermore, a notch may be formed in the inclined portion 8.

[0049] It is preferable that the linear member 10 is fixed to the cylindrical body 2 at the proximal extension portion 7 where the proximal opening 5 is formed. It is preferable that the linear member 10 extends distal to the distal end of the proximal opening 5, i.e., to the cylindrical portion 3. Therefore, it is preferable that the distal end of the linear member 10 is located distal to the distal end of the proximal opening 5. In this case, it is preferable that the linear member 10 is fixed to the cylindrical portion 3 and the proximal extension portion 7. This makes it easier for the cylindrical body 2 to bend smoothly from the proximal extension portion 7 to the cylindrical portion 3 when a bending force is applied to the proximal portion of the cylindrical body 2, and makes it less likely for the cylindrical portion 3 to bend irregularly or for kinks to occur in the cylindrical portion 3.

[0050] Preferably, the proximal extension portion 7 is located proximal to the inclined portion 8 and has a strip-shaped portion 9 that extends parallel to the longitudinal axis x. By providing the strip-shaped portion 9 in this way, it becomes easier to insert the treatment device along the strip-shaped portion 9 from the proximal opening 5 of the cylindrical body 2.

[0051] The strip-shaped portion 9 is formed on the upper part of the cylindrical body 2, and the linear member 10 is preferably arranged along the strip-shaped portion 9 and fixed to the strip-shaped portion 9. The length x in the longitudinal axis direction of the strip-shaped portion 9 is preferably 50 mm or more, more preferably 80 mm or more, even more preferably 100 mm or more, and preferably 200 mm or less, more preferably 180 mm or less, and even more preferably 150 mm or less. This allows the linear member 10 to be stably fixed to the cylindrical body 2.

[0052] The cylindrical portion 3 of the cylindrical body 2 has a resin layer and a reinforcing layer in which metal wires or fibers are arranged in a helical, mesh, or braided manner. Preferably, the proximal end of the reinforcing layer is within 15 mm distal to the distal end of the proximal opening 5, more preferably within 10 mm, and even more preferably within 8 mm. By providing the reinforcing layer in this way, the lumen 4 of the cylindrical body 2 becomes less likely to collapse, and it becomes easier to insert a treatment device into the lumen 4 of the cylindrical body 2. Preferably, the resin layer of the cylindrical portion 3 includes the inner layer and outer layer described above.

[0053] The proximal extension portion 7 of the tubular body 2 preferably has the inner layer and outer layer described above. It is preferable that the proximal extension portion 7 does not have a reinforcing layer. This allows the proximal extension portion 7 to bend more easily than the tubular portion 3 of the tubular body 2 when the proximal end of the tubular body 2 is located in a curved portion of a body cavity such as a blood vessel or a curved portion of a guide catheter, thereby suppressing excessive distortion of the tubular portion 3 or the occurrence of kinks in the tubular portion 3.

[0054] This application claims the benefit of priority based on Japanese Patent Application No. 2021-169115, filed on 14 October 2021. The entire specification of Japanese Patent Application No. 2021-169115, filed on 14 October 2021, is incorporated herein by reference. [Explanation of symbols]

[0055] 1: Extension guide catheter 2: Cylindrical body 3: Cylindrical part 4: Lumen 5: Proximal opening 6: Distal opening 7: Proximal extension 8: Inclined part 9: Band-shaped area 10: Linear member 11: 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 cylindrical body has an upper side to which the linear member is fixed and a lower side on the opposite side in the radial direction. The cylindrical body has a cylindrical portion and a non-cylindrical proximal extension portion extending proximal to the cylindrical portion, the proximal opening is formed in the proximal extension portion, and the proximal extension portion has an inclined portion that slopes distally from the top to the bottom. The lumen of the cylindrical body has a shape that satisfies the following requirements at the proximal end of the cylindrical portion: An extension guide catheter in which the proximal end of the tubular portion is formed such that the wall thickness of the upper and lower portions of the tubular body is thicker than the wall thickness of the portion in between. [Requirements] In a vertical cross-section of the lumen in the longitudinal direction, let L1 be the length of the portion where a first imaginary line passing through the linear member and extending vertically overlaps the lumen (hereinafter referred to as the "first imaginary line segment"), and let L2 be the length of the portion where a second imaginary line passing through the midpoint of the first imaginary line segment and extending perpendicularly to the first imaginary line overlaps the lumen (hereinafter referred to as the "second imaginary line segment"), then L1 is longer than L2.

2. The extension guide catheter according to claim 1, wherein L1 is 1.02 times or more and 1.50 times longer than L2.

3. The extension guide catheter according to claim 1, wherein the inclined portion is inclined distally from the top to the bottom, forming an angle of 5° to 60° with respect to the longitudinal axis of the cylindrical body in a plan view formed from the longitudinal axis and the top and bottom directions.

4. The extension guide catheter according to claim 1, wherein the linear member extends distally from the distal end of the proximal opening and is fixed to the tubular portion and the proximal extension portion.

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