JP2012000328A - Stent delivery catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stent delivery catheter with which a stent can be mounted easily and the stent can be easily delivered.SOLUTION: A cylindrical marker 11 is intervened between an outer layer 31T and a reinforcing layer 31M in the part of an outer tube 31 for storing a stent 29 at the end of an outer tube 31. The cylindrical marker 11 is attached and pressed to a wire contained in the reinforcing layer 31M and, together with the reinforcing layer 31M, is covered with an outer layer 31T.

Description

  The present invention relates to a stent delivery catheter for delivering a stent.

  Stents generally treat a variety of diseases caused by stenosis or occlusion of blood vessels or other in vivo lumens. Specifically, a stent is a medical device that is placed in order to expand a stenosis or occlusion site and maintain its lumen size.

  Examples of the stent include a coil type made of a single linear metal or polymer material, a type in which a metal tube is cut out by a laser, a type in which a linear member is assembled by welding with a laser, or There are types made by weaving multiple linear metals.

  These stents are expanded by a balloon mounted with the stent (balloon expandable type), and are expanded by removing members that suppress expansion from the outside (self-expandable). Type).

  For example, the self-expandable type is generally used in the vicinity of the distal end of an intravascular catheter and covered with a sheath or the like. More specifically, the catheter is advanced to the treatment site in the body lumen of the patient, the sheath or the like is removed at the treatment site, and the stent is placed by self-expansion along with this. In recent years, these stents have been frequently used for ureteral, bile duct, or lower limb arthroplasty.

  When a self-expandable stent is delivered to a target lesion, the stent is generally inserted into a delivery catheter (note that a delivery catheter equipped with a stent is referred to as a stent delivery catheter). The delivery catheter itself may be referred to as a stent delivery catheter).

  In the case of such insertion, the stent is contracted (crimped) to be equal to or smaller than the inner diameter of the outer tube of the delivery catheter. And such a stent is separated from an outer tube, and is arrange | positioned in a lesioned part after conveying to a lesioned part with a delivery catheter.

  Examples of such a stent delivery catheter include Patent Documents 1 to 3.

  The stent delivery catheter described in Patent Document 1 includes a structure having a locking stay on a shaft. However, this stent delivery catheter prevents the stent from jumping and stretching when the stent is indwelled, but the manufacture of the stent delivery catheter becomes complicated.

  In the stent delivery catheter described in Patent Document 2, the vicinity of the distal end of the stent housing portion is tapered so as to gradually increase in diameter toward the distal end side, and further, the outer surface of the tube body arranged in the sheath and the distal end of the sheath The structure which contacts is included. However, this stent delivery catheter is not likely to be unremovable from the body when the tube body is removed, but it cannot prevent the stent from being jumped or stretched when it is placed.

  The stent delivery catheter described in Patent Document 3 includes a structure in which an expandable member is provided on the catheter shaft, and a stop member is provided on the expandable member. However, the stent delivery catheter cannot prevent stent jumping or expansion / contraction.

  As described above, various stent delivery catheters exist. Generally, a stent crimping apparatus is used for crimping a stent. Furthermore, the distal end of the delivery catheter is brought into contact with the crimping head of the stent crimping device (the portion that reduces the diameter of the stent), and the stent is inserted into the lumen of the delivery catheter.

Japanese Patent No. 3679466 Japanese Patent No. 3754055 Special table 2008-504880

  However, if the distal end of the delivery catheter is flexible, buckling occurs when it comes into contact with the crimping head, and the stent is difficult to be inserted into the lumen of the delivery catheter.

Also, if the delivery catheter tip is flexible, even when the stent is placed in the lesion, the friction between the stent and the delivery catheter tip becomes too great, and the stent is placed in a stretched state. It may be difficult to place itself. As a result, for example, there is a problem that the prognosis of the patient is greatly affected, an excessive load is applied to the delivery catheter, the delivery catheter itself is damaged, or the stent and the delivery catheter are stuck in the body lumen. Problems can occur.
The present invention has been made to solve the above problems. And the objective is to provide the stent delivery catheter which is easy to mount | wear with a stent and is easy to convey a stent.

  The stent delivery catheter includes a multi-layered shaft tube that houses a stent. In this stent delivery catheter, the shaft tube includes an inner layer surrounding the hollow, a reinforcing layer covering the inner layer, and an outer layer covering the reinforcing layer. In addition, a tubular portion is interposed between the outer layer and the reinforcing layer in the portion of the shaft tube that accommodates the stent at the end of the shaft tube, and the tubular portion is included in the end of the reinforcing layer. It is crimped to the wire and is covered with the outer layer together with the reinforcing layer.

  The reinforcing layer is preferably formed to include at least one of a metal strand and a synthetic resin strand.

  Moreover, it is preferable that the strand is formed in at least one of a braided structure and a coil structure.

  The stent is preferably a self-expandable stent.

  The tubular portion is preferably formed of one or more materials selected from the group consisting of stainless steel, nickel titanium alloy, tungsten, tantalum, gold, platinum, iridium, and palladium.

  According to the stent delivery catheter of the present invention, it is easy to mount the stent and to transport the stent.

FIG. 3 is a cross-sectional view of a stent delivery catheter. FIG. 3 is a perspective view of a stent. These are explanatory drawings of the apparatus used for evaluation with respect to a stent delivery catheter. These are explanatory drawings of the apparatus used for evaluation with respect to a stent delivery catheter.

[Embodiment 1]
The following describes one embodiment with reference to the drawings. For convenience, hatching, member codes, and the like may be omitted, but in such a case, other drawings are referred to. In addition to the cross-sectional view, hatching may be added for convenience.

  FIG. 1 shows an example of a stent delivery catheter 69. The stent delivery catheter 69 is used to transport the stent 29 to a lesioned portion (stenosis portion) of a blood vessel, and is elongated and flexible so that it can be inserted into a lumen (from the stent delivery catheter 69, The one from which the stent 29 is removed may be referred to as a delivery catheter or a stent delivery catheter).

  The stent delivery catheter 69 includes a stent 29, an outer shaft 39, and an inner shaft 49 (in other words, the stent delivery catheter 69 includes a stent 29 and a delivery catheter having the outer shaft 39 and the inner shaft 49. ).

  As shown in FIG. 2, the stent 29 is formed by an annular substantially corrugated component [annular element] 22 continuing in an axial direction that is one direction, and the substantially corrugated component 22 is an elongated strut 21. It is formed by connecting

  In the stent 29 as shown in FIG. 2, the outer diameter OD and the axial length LD are appropriately selected according to the inner diameter and length of the lesioned lumen, and depend on the target lumen for treatment. Different. For example, in the superficial femoral artery stent 29, the outer diameter OD is set to about 6.0 mm to 10.0 mm, and the axial length LD is set to about 30 mm to 200 mm.

  The stent 29 is formed, for example, by subjecting a nickel-titanium alloy pipe to laser cutting to expand the diameter and heat-treat.

  The outer shaft 39 includes an outer tube [shaft tube] 31 that accommodates the stent 29 in a reduced diameter state. The stent 29 is a self-expandable stent that expands and treats a stenosis of a blood vessel. When the restriction by the lumen 32 of the outer tube 31 is released, the inner diameter of the stent 29 is the outer diameter of the outer tube 31. The diameter is expanded as described above, and the outer diameter after the expansion is determined.

  Further, the outer tube 31 is a member having flexibility enough to follow a lumen (blood vessel or the like) to be inserted, kink resistance, and a tensile strength that does not extend when the stent delivery catheter 69 is pulled during the procedure. Formed with.

  Further, when the outer tube 31 is moved, the inner layer of the outer tube 31 reduces the movement resistance (sliding resistance) with the stent 29 in contact with the inner peripheral surface of the layer, and the outer tube 31 It has a smoothness so that it can be easily moved.

  From the viewpoint of satisfying the above characteristics, the outer tube 31 has an outer layer (outer layer tube) 31T and an inner layer (inner layer tube) 31N formed of a resin material, and a metal wire between the outer layer 31T and the inner layer 31N. This layer (reinforcing layer) is preferably formed of a three-layer resin-metal composite tube embedded with 31M.

  The outer layer 31T is a layer that covers the reinforcing layer 31M, and has a thickness of about 50 to 120 μm, for example. Examples of the material of the outer layer 31T include various elastomers such as polyamide elastomer, polyester elastomer, polyurethane elastomer, polystyrene elastomer, fluorine elastomer, silicone rubber, latex rubber, or a combination of two or more thereof. It is done.

  Examples of polyamide elastomers include nylon 6, nylon 64, nylon 66, nylon 610, nylon 612, nylon 46, nylon 9, nylon 11, nylon 12, N-alkoxymethyl modified nylon, hexamethylenediamine-isophthalic acid. Examples thereof include block copolymers in which various aliphatic or aromatic polyamides such as polymers or metaxyloyldiamine-adipic acid condensation polymers are used as hard segments, and polymers such as polyesters and polyethers are used as soft segments. .

  In addition, a polymer alloy (polymer blend, graft polymerization, random polymerization, etc.) of the above-mentioned polyamide and a flexible resin, or the above-mentioned polyamide softened with a plasticizer or the like, The concept including these mixtures is polyamide elastomer.

  The polyester elastomer is typically a block copolymer of a saturated polyester such as polyethylene terephthalate or polybutylene terephthalate and a polyether or polyester. In addition, these polymer alloys and saturated polyesters can be softened with a plasticizer or the like. It is a concept including a mixture of these, and a mixture thereof.

  From the viewpoint of processability and flexibility, an example of an excellent polyamide elastomer is Pebax or Rilsan manufactured by ARKEMA.

  The reinforcing layer 31M is a layer that is covered with the outer layer 31T, and is a layer that includes at least one of a synthetic resin strand and a metal strand (in short, the reinforcing layer 31M is made of only a synthetic resin strand. It may be formed only with a metal strand, or may be formed with a synthetic resin strand and a metal strand).

  In addition, the synthetic resin strand or the metal strand may be formed of the strand alone, or may be formed of an assembly strand (for example, a twisted or bundled strand).

  In addition, the metal strand is formed of at least one of a braided structure and a coil structure, and is preferably formed from one end to the other end in the length of the outer tube 31 (note that the operator The side close to the hand of the hand is called the proximal end, and the opposite side to the proximal end is called the distal end).

  In addition, as a material of a synthetic resin strand, for example, polyesters such as polyethylene terephthalate, polybutylene terephthalate, polymethylene terephthalate, polyolefins such as polyethylene and polypropylene, rigid polyvinyl chloride, polyamide, polyimide, polystyrene, thermoplastic polyurethane , Polycarbonate, ABS resin, acrylic resin, polymethyl methacrylate, polyacetal, polyarylate, polyoxymethylene, high tensile polyvinyl alcohol, fluororesin, polyvinylidene fluoride, polytetrafluoroethylene, saponified ethylene-vinyl acetate, polysulfone, polyethersulfone , Aromatic polyaramide represented by polyetherketone, polyphenylene oxide, polyphenylene sulfide, Kevlar , Polymer alloy containing any of these, carbon fibers, or glass fibers and the like.

  In addition, as the material of the metal wire, stainless steel, copper, tungsten, nickel, titanium, piano wire, Co-Cr alloy, Ni-Ti alloy, Ni-Ti-Co alloy, Ni-Al alloy, Cu-Zn alloy, Various metal strands such as a superelastic alloy such as a Cu—Zn—X alloy (for example, X = Be, Si, Sn, Al, Ga) or an amorphous alloy can be given.

  Of these materials, stainless steel is preferred for reasons such as workability, economy, and lack of toxicity. The metal wire is preferably a flat wire from the viewpoint of kink resistance or elongation resistance. For example, the thickness is preferably set to about 10 to 40 μm and the width is set to about 80 to 120 μm.

  The inner layer 31N is a layer covered with the reinforcing layer 31M, and has a thickness of about 10 to 50 μm, for example. And as a material of inner layer (inner layer pipe) 31N, for example, polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, ethylene-tetrafluoroethylene copolymer Fluorine resin such as coalescence, polyolefin such as polypropylene, polyethylene, ethylene-vinyl acetate copolymer, polyester such as polyamide, polyethylene terephthalate, polybutylene terephthalate, polyurethane, polyvinyl chloride, polystyrene resin, polyimide resin, or , And mixtures thereof.

  In addition, with respect to the stent 29 that passes through the lumen of the outer tube 31 that the inner layer 31N faces, from the viewpoint of having excellent lubricity, it is a polytetrafluoroethylene or a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, The inner layer 31N is preferably formed.

  By the way, the multilayer outer tube 31 described above includes the cylindrical marker 11, which will be described in detail later.

  The inner shaft 49 includes an inner tube 41, a pusher marker 43, a core wire 45, and a tip tip 47.

  The inner tube 41 is a tube having a hollow (lumen) (not shown), and at least a part thereof is inserted into the lumen 32 of the outer tube 31 of the outer shaft 39. A guide wire (not shown) is inserted into the lumen formed in the inner tube 41 to guide the outer shaft 39 to the lesioned part.

  The inner tube 41 is flexible enough to follow the inserted lumen (the lumen 32 of the outer tube 31), has kink resistance, and has a tensile strength that does not extend when the catheter is pulled during the procedure. .

  For example, fluorine resins such as polyimide, polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, ethylene-tetrafluoroethylene copolymer, polypropylene, polyethylene, Polyolefin such as ethylene-vinyl acetate copolymer, polyester such as polyamide, polyethylene terephthalate, polybutylene terephthalate, resin such as polyurethane, polyvinyl chloride, polystyrene resin, polyimide, or a mixture of them is the inner tube 41. As a material of From the viewpoint of lubricity and tensile strength, it is preferable that the inner tube 41 is formed of polyimide.

  The pusher marker 43 is fitted (adhered or welded) around the inner tube 41, fits in the lumen 32 of the outer tube 31, and pushes out the stent 29 from the outer tube 31 as the inner tube 41 moves.

  Therefore, the position of the pusher marker 43 is preferably equal to or longer than the distance of the axial length (full length) of the stent 2 from the tip of the inner tube 41 (the dimension of the pusher marker 43 is appropriately set. Is preferably about 100 to 200 μm and the total length is about 1.0 to 3.0 mm).

  Examples of the material of the pusher marker 43 include one or more materials selected from the group consisting of stainless steel, nickel titanium alloy, tungsten, tantalum, gold, platinum, iridium, and palladium. For example, from the viewpoint of strength, workability, or economic efficiency, stainless steel is preferable as the material of the pusher marker 43.

  Further, when the pusher marker 43 is formed of a radiopaque material, the distal end of the stent delivery catheter 69 is advanced while being visually recognized to the lesioned part in the body lumen under fluoroscopy. In addition, when the stent 29 is disposed, the positional relationship between the stent 29 and the delivery catheter (the stent delivery catheter 69 excluding the stent 29) is also confirmed. Therefore, the stent delivery catheter 69 can transport and release the stent 29 more safely and efficiently.

  The core wire 45 is connected in parallel with the inner tube 41 and is further connected to the pusher marker 43. Specifically, a part of the side surface of the core wire 45 is connected to the inner tube 41, and an end portion of the core wire 45 is connected to one surface of the pusher marker 43 facing the proximal end side (in short, the core wire 45 is It is partially bonded or welded to the inner tube 41 and the pusher marker 43).

  In this case, the operator's force through the operation unit 51 connected to the inner tube 41 and the core wire 45 is not lost to the inner tube 41 and the core wire 45 (that is, the inner shaft 49). It is transmitted. Therefore, the stent delivery catheter 69 carrying the inner shaft 49 can place the stent 29 more safely and efficiently.

  Moreover, as a material of the core wire 45, materials, such as stainless steel or a nickel titanium alloy, are mentioned. In view of strength, workability, or economic reasons, stainless steel is preferable as the material of the core wire 45.

  Moreover, although the dimension of the core wire 45 is set suitably, it is preferable when an outer diameter is set to about 0.20-0.60 mm, for example. Further, the core wire 45 and the inner tube 41 may be integrated by a resin or a metal tube.

  The tip tip 47 is bonded or welded to the tip of the inner tube 41. The distal tip 47 makes it easier for the stent delivery catheter 69 to pass through the lesion (stenosis). Moreover, it is preferable that the front-end | tip chip | tip 47 has contrast property. In this way, the distal end of the stent delivery catheter 69 is grasped. Further, the relative position of the stent 29 with respect to the vicinity of the distal end (distal end) of the outer tube 31 is grasped by the operation of the operator using the operation portion 51 attached to the proximal end of the inner shaft 49.

  Note that the distal tip 47 is a member having flexibility enough to follow a lumen (blood vessel or the like) to be inserted and rigidity in the major axis direction enough to pass through the narrowed portion. For example, various elastomers such as polyamide elastomer, polyester elastomer, polyurethane elastomer, polystyrene elastomer, fluorine elastomer, silicone rubber, latex rubber, or a combination of two or more of these may be used as the material for the tip chip 47. . Furthermore, from the viewpoint of adding contrast, it is preferable that the tip tip 47 contains barium sulfate, a bismuth compound, a tungsten compound, or the like.

  Here, the cylindrical marker [tubular portion] 11 included in the outer tube 31 will be described in detail. The outer tube 31 includes an inner layer 31N surrounding the hollow (lumen 32), a reinforcing layer 31M covering the inner layer 31N, and an outer layer 31T covering the reinforcing layer 31M. And the cylindrical marker 11 is arrange | positioned at the front-end | tip of the outer tube 31, and is crimped | bonded on the reinforcement layer 31M, as shown in FIG.

  More specifically, the cylindrical marker 11 is interposed between the outer layer 31T and the reinforcing layer 31M in the portion of the outer tube 31 that houses the stent 29 at the end of the outer tube 31. Further, the cylindrical marker 11 is pressure-bonded to a strand included at the end of the reinforcing layer 31M, and is covered with the outer layer 31T together with the reinforcing layer 31M.

  If it becomes like this, the front-end | tip (as a result, the front-end | tip of a delivery catheter) of the outer tube 31 will become hard. Therefore, when the reduced diameter stent 29 is inserted into the distal end of the lumen 32 of the outer tube 31 with a pressing member (for example, a metal pusher) made of metal or the like, the distal end of the outer tube 31 is inserted. Does not buckle. Therefore, the stent 29 is easily inserted into the lumen 32 of the outer tube 31.

  In addition, in this stent delivery catheter 69, when the stent 29 is disposed at the lesion, the distal end of the outer tube 31 does not buckle, so that the friction between the lumen 32 at the distal end and the stent 29 is reduced. Therefore, this stent delivery catheter 69 can arrange the stent 29 safely and easily.

  Examples of the material of the cylindrical marker 11 include one or more relatively hard materials selected from the group consisting of stainless steel, nickel titanium alloy, tungsten, tantalum, gold, platinum, iridium, and palladium. In addition, platinum-iridium alloy is preferable as the material of the cylindrical marker 11 from the reasons of radiopacity, strength, workability, antibacterial property, or economic efficiency.

  Further, when the cylindrical marker 11 is formed of a radiopaque material, the distal end of the stent delivery catheter 69 is advanced to the lesioned part in the body lumen while being viewed through the X-ray fluoroscopy. In addition, when the stent 29 is placed, the positional relationship between the stent 29 and the delivery catheter is also confirmed. Therefore, the stent delivery catheter 69 can transport and release the stent 29 more safely and efficiently.

  Moreover, although the dimension of the cylindrical marker 11 is set suitably, for example, it is preferable when thickness is set to about 20-80 micrometers and length is set to about 1.0-3.0 mm.

  In addition, below, specific Example 1 and Comparative Example 1 were shown and evaluated. However, the stent delivery catheter 69 is not limited to this example.

[Example 1]
In the outer tube 31 of the outer shaft 39, the inner layer 31N has a tube shape (inner layer tube) having a thickness of 40 μm and an inner diameter of 1.78 mm, and is formed of polytetrafluoroethylene.

  On the inner layer 31N, a reinforcing layer 31M braided using 16 strands of SUS304 having a thickness of 25 μm and a width of 100 μm is covered. Then, a platinum-iridium cylindrical marker 11 having a thickness of 50 μm, a length of 1.0 mm, and an inner diameter of 2.0 mm is caulked at the end of the inner layer tube (inner layer tube) 31N covered with the reinforcing layer 31M.

  Further, the cylindrical marker 11 is pressure-bonded to the strand near the end of the reinforcing layer 31M. Thereafter, the strand on the tip side from the cylindrical marker 11 is removed by a YAG laser, and the remaining strand or the like is subjected to electrolytic polishing.

  The inner layer tube 31N covered with the reinforcing layer 31M to which the cylindrical marker 11 is attached is covered with the outer layer 31T and further covered with a heat shrinkable tube, and then heated. After the heating, the heat shrinkable tube is removed, and the extra outer layer 31T at the end of the cylindrical marker 11 is cut off with a razor.

  The outer layer 31T is a tube having a thickness of 125 μm and an inner diameter of 1.75 mm made of a material obtained by blending Pebax7033 SA01 (ARKEMA) having a Shore D hardness of 70 and Rilsan-AESN (ARKEMA) at a ratio of 3: 1. It is.

  In the inner shaft 49, as the inner tube 41, a tube made of polyimide and having a thickness of 20 μm and an inner diameter of 0.53 mm was used.

  The tip chip 47 is made of polyamide elastomer and is bonded to the tip of the inner tube 41 with an adhesive.

  The pusher marker 43 was formed of SUS304, and a cylindrical tube having a thickness of 180 μm and an inner diameter of 1.25 mm was used. The pusher marker 43 is adhered with an adhesive at a position 50 mm from the tip of the inner tube 41.

  As the core wire 45, a wire formed of SUS304 and having an outer diameter of 0.45 mm was used. The core wire 45 and the inner tube 41 are integrated by covering and welding with a tube having a thickness of 175 μm and an inner diameter of 1.25 mm formed of Pebax 5533 having a Shore D hardness of 55.

  Further, stainless steel was used as the material of the operation unit 51.

  The stent 29 is a self-expandable type. In this stent, a nickel titanium alloy pipe with a diameter of φ3.0 mm is laser-cut and expanded to φ8 mm and subjected to heat treatment. The outer diameter OD of the stent 29 was 8 mm, and the axial length LD was 40 mm.

[Comparative Example 1]
The outer tube in the outer shaft uses the inner layer, the reinforcing layer, the outer layer, and the cylindrical marker similar to those in the first embodiment, and is manufactured by substantially the same manufacturing method.

  That is, as in Example 1, a braided reinforcing layer is covered on the inner layer tube, and a platinum-iridium cylindrical marker is caulked at the end of the inner layer tube covered with the reinforcing layer (Comparative Example) The various sizes, materials, and the like of the inner layer, the reinforcing layer, and the cylindrical marker in 1 are the same as those in Example 1.

  Further, as in Example 1, after the cylindrical marker was pressure-bonded to the strand near the end of the reinforcing layer, the strand on the tip side of the cylindrical marker was removed with a YAG laser, and the remaining strand, etc. In contrast, electrolytic polishing is performed.

  In addition, as in Example 1, the outer layer is covered on the inner layer tube covered with the reinforcing layer to which the cylindrical marker is attached (Note that various sizes and materials of the outer layer in Comparative Example 1 are the same as those in Example 1. Further, after the heat shrinkable tube is put on, it is heated. And a heat shrinkable tube is removed after a heating.

  The difference between Example 1 and Comparative Example 1 is that in Example 1, only the extra outer layer 31T at the end of the cylindrical marker is cut off with a razor. In Comparative Example 1, the cylindrical marker and the cylindrical marker are cut off. The excess outer layer at the end of the is cut off with a razor. Thereby, the outer tube which does not have a cylindrical marker is completed.

  In addition to the above differences, for example, various sizes and materials related to the tip, pusher marker, core wire, and operation unit are the same in Comparative Example 1 and Example 1.

[Evaluation]
The following evaluations (1) and (2) were carried out for Example 1 and Comparative Example 1 described above.

(1) Evaluation of stent crimping The insertion property in the case of inserting a stent into a catheter was evaluated. In this evaluation, a self-expanding stent crimping apparatus (SC900 manufactured by Machine Solutions Inc) 79 as shown in FIG. 3 was used.

  Specifically, the crimping head 71 of the stent crimping device 79 sandwiches the stent, and after crimping the stent, the distal end of the delivery catheter is brought close to the end of the crimping head (note that the crimping of the stent is the crimping head). The speed was 1 mm / s, and crimping was performed as a pre-crimp to an outer diameter of 4 mm, and finally to an outer diameter of 1.72 mm).

  Then, when the stent is pushed by the metal pusher 73, the stent is inserted into the lumen of the delivery catheter. The possibility of this insertion was evaluated (note that the number of samples is five).

(2) Stent release load and shortening evaluation The load when the stent was released from the delivery catheter was evaluated. As shown in FIG. 4, a model (simulated blood vessel 82) simulating a lower limb blood vessel including a bent portion with a radius of curvature (R) of 15 mm is immersed in a warm bath 81 at 37 ° C. ± 2 ° C. The simulated blood vessel 82 is a PFA tube having a thickness of 2 mm and an inner diameter of 6 mm.

  Then, when the slider 83 that holds the outer shaft moves (see the white arrow), the stent inserted into the lumen of the delivery catheter is released. In the case of this release, the load is transmitted to a force gauge (manufactured by Nidec Symposium) 84 attached near the proximal end of the inner shaft and the load is measured (note that the number of samples is one). is there).

  More specifically, in a model 82 simulating a blood vessel of a lower limb, a 6Fr sheath (Shuffle Sheath; Cook) and a 0.018-inch guidewire (Radiforcus; TRUMO) are inserted into the sheath. A delivery catheter is placed. In addition, the outer tube is pulled by the slider 83 while the inner tube is fixed, and the stent release load is measured (the smaller the stent release load, the better the release performance of the stent).

  At the same time, the shortening after placement of the stent was also calculated. The shortening of the stent was calculated by the following formula (note that the smaller the shortening, the better the release performance of the stent).

shortening(%)
= (Stent length when crimped-Stent length when placed) x 100 / Stent length when crimped

[Evaluation results]
The evaluation results are as follows.

(1) Crimping success rate [%]
Example 1 100% (5/5)
Comparative Example 1 20% (1/5)
(2) Stent discharge load [N] Shortening [%]
Example 1 12.00N 6.67%
Comparative Example 1 15.84N 29.55%

  From the evaluation result (1), in Comparative Example 1, only one of the five samples could be inserted into the delivery catheter after crimping, whereas in Example 1, all the samples were crimped. Could be inserted into the delivery catheter.

  Further, from the evaluation result (2), compared with Comparative Example 1, Example 1 has smaller values for both the stent release load and shortening, and the release performance of the stent is excellent.

11 Cylindrical marker [tubular part]
21 Strut 22 Roughly corrugated component 29 Stent 31 Outer tube [Shaft tube]
31N Inner layer 31M Reinforcement layer 31T Outer layer 32 Lumen 39 Outer shaft 41 Inner tube 43 Pusher marker 45 Core wire 47 Tip tip 49 Inner shaft 69 Stent delivery catheter 71 Crimping head 73 Metal pusher 79 Stent crimping device 81 Warm bath 82 Simulated blood vessel 83 Slider 84 Force gauge

Claims (5)

A stent delivery catheter including a multi-layered shaft tube that houses a stent,
The shaft tube includes an inner layer surrounding a hollow, a reinforcing layer covering the inner layer, and an outer layer covering the reinforcing layer,
At the end of the shaft tube, the portion of the shaft tube that houses the stent has a tubular portion interposed between the outer layer and the reinforcing layer,
The tubular delivery portion is a stent delivery catheter that is pressure-bonded to an element wire included at an end of the reinforcing layer, and is covered with the outer layer together with the reinforcing layer.   The stent delivery catheter according to claim 1, wherein the reinforcing layer includes at least one of a metal strand and a synthetic resin strand.   The stent delivery catheter according to claim 2, wherein the strand is formed in at least one of a braided structure and a coil structure.   The stent delivery catheter according to any one of claims 1 to 3, wherein the stent is a self-expandable stent. The tubular portion is formed of one or more materials selected from the group consisting of stainless steel, nickel titanium alloy, tungsten, tantalum, gold, platinum, iridium, and palladium. Stent delivery catheter.