Tube stent delivery system and manufacturing method of tube stent delivery system

Abstract

To suppress peeling of an inner layer 30 and an outer layer 32 of a tube stent 6.SOLUTION: A tube stent delivery system 1 includes: an inner catheter 2 into which a guide wire GW is inserted; an outer catheter 4 into which the inner catheter 2 is inserted; and a tube stent 6 which is arranged more on a tip side of the inner catheter 2 than the outer catheter 4 and into which the inner catheter 2 is inserted. The outer catheter 4 is composed of a material containing PTFE. The tube stent 6 includes an inner layer 30 for sectioning a third lumen composed of a material containing PTFE, into which the inner catheter 2 is inserted, and an outer layer 32 for covering the inner layer 30. Strength at 50% elongation per unit area of the inner layer 30 in an axial direction of the tube stent 6 is smaller than strength at 50% elongation per unit area of the outer catheter 4 in an axial direction of the outer catheter 4.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates to a tubular stent delivery system and a method for manufacturing the tubular stent delivery system. [Background technology]

[0002] Patent Document 1 discloses an indwelling tube guide device (tube stent delivery system) for placing a residual tube (tube stent) as a stent in a narrowed portion of a bile duct. This indwelling tube guide device includes an indwelling tube, a pusher tube for moving the indwelling tube, and a guide catheter inserted into the indwelling tube and the pusher tube. The guide catheter carrying the indwelling tube and the pusher tube is guided along a guidewire to the narrowed portion of the bile duct, and the indwelling tube is placed in the narrowed portion by being pushed out by the pusher tube. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2003 / 092782 Summary of the Invention [Problem to be solved by the invention]

[0004] It is desirable for the indwelling tube to have a material that is difficult for the drainage target, such as bile, to adhere to its inner surface. Polytetrafluoroethylene is known as a material to which the drainage target does not easily adhere. On the other hand, it is desirable for the indwelling tube to have a suitable degree of flexibility from the viewpoint of ease of delivery to the target site in the body.

[0005] One method for imparting these properties to an indwelling tube is to make the indwelling tube have a two-layer structure consisting of an outer layer and an inner layer, with the inner layer being made of polytetrafluoroethylene and the outer layer being made of a flexible material. However, when making an indwelling tube into a two-layer structure, it is required that the inner layer and the outer layer do not peel off from each other.

[0006] The present disclosure has been made in light of these circumstances, and has an objective to provide a technique for suppressing peeling between the inner layer and the outer layer of a tube stent. [Means for solving the problem]

[0007] An embodiment of the present disclosure is a tube stent delivery system. The delivery system includes an inner catheter having a first lumen through which a guidewire is passed, an outer catheter having a second lumen through which the inner catheter is passed, and a tube stent having a third lumen through which the inner catheter is passed and disposed on the distal end side of the inner catheter relative to the outer catheter. The outer catheter is made of a material containing polytetrafluoroethylene. The tube stent has an inner layer made of a material containing polytetrafluoroethylene and defining the third lumen, and an outer layer covering the inner layer. The strength of the inner layer per unit area in the axial direction of the tube stent at 50% stretching is lower than the strength of the outer catheter per unit area in the axial direction of the outer catheter at 50% stretching.

[0008] Another aspect of the present disclosure is a tube stent delivery system. This delivery system includes an inner catheter having a first lumen through which a guidewire is passed, an outer catheter having a second lumen through which the inner catheter is passed, and a tube stent having a third lumen through which the inner catheter is passed and disposed on the distal end side of the inner catheter relative to the outer catheter. The outer catheter is made of a material containing polytetrafluoroethylene. The tube stent has an inner layer that is made of a material containing polytetrafluoroethylene and defines the third lumen, and an outer layer that covers the inner layer. The molecular orientation of the inner layer in the axial direction of the tube stent is lower than the molecular orientation of the outer catheter in the axial direction of the outer catheter.

[0009] Another aspect of the present disclosure is a method for manufacturing a tube stent delivery system including an inner catheter having a first lumen through which a guidewire is passed, an outer catheter having a second lumen through which the inner catheter is passed, and a tube stent having a third lumen through which the inner catheter is passed and disposed on the distal end side of the inner catheter relative to the outer catheter. The tube stent has an inner layer made of a material containing polytetrafluoroethylene and defining the third lumen, and an outer layer covering the inner layer. This manufacturing method includes forming the outer catheter by extruding a paste of a material containing polytetrafluoroethylene, and forming the inner layer by applying a dispersion of a material containing polytetrafluoroethylene.

[0010] Any combination of the above components and any conversion of the expression of the present disclosure between a method, an apparatus, a system, etc. are also valid as aspects of the present disclosure. Effect of the Invention

[0011] According to the present disclosure, peeling between the inner layer and the outer layer of a tube stent can be suppressed. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a side view of a tube stent delivery system according to an embodiment. [Diagram 2] Fig. 2(A) is a side view of the inner catheter, and Fig. 2(B) is a cross-sectional view taken along line AA in Fig. 2(A). [Diagram 3] Fig. 3(A) is a side view of the outer catheter, and Fig. 3(B) is a cross-sectional view taken along line BB in Fig. 3(A). [Figure 4] Fig. 4(A) is a side view of a tube stent, and Fig. 4(B) is a cross-sectional view taken along line CC in Fig. 4(A). [Diagram 5] FIG. 2 is a schematic diagram showing a tube stent in use. [Figure 6] FIG. 1 is a cross-sectional view of a tube stent delivery system and a guidewire. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The present disclosure will be described below with reference to the drawings based on preferred embodiments. The embodiments are illustrative and do not limit the present disclosure, and all features and combinations thereof described in the embodiments are not necessarily essential to the present disclosure. The same or equivalent components, members, and processes shown in each drawing are given the same reference numerals, and duplicated descriptions are omitted as appropriate. In addition, the scale and shape of each part shown in each drawing are set for convenience to facilitate explanation, and are not to be interpreted as being limiting unless otherwise specified. In addition, when terms such as "first" and "second" are used in this specification or claims, unless otherwise specified, these terms do not represent any order or importance, but are intended to distinguish one configuration from another. In addition, some of the members that are not important in explaining the embodiment in each drawing are omitted.

[0014] 1 is a side view of a tube stent delivery system 1 according to an embodiment. The tube stent delivery system 1 (hereinafter, appropriately abbreviated as "delivery system 1") comprises an inner catheter 2, an outer catheter 4, and a tube stent 6. The inner catheter 2 and the outer catheter 4 constitute a delivery device, and the delivery system 1 is constructed by assembling the tube stent 6, which is the object of delivery, to the delivery device.

[0015] One end of the delivery system 1 is inserted into the body, and the other end is placed outside the body. Hereinafter, the side of the delivery system 1 that is inserted into the body is referred to as the "distal side", and the side that is placed outside the body is referred to as the "base side". In addition, for each member constituting the delivery system 1, the same side as the distal side of the delivery system 1 is referred to as the "distal side" of that member, and the same side as the base side of the delivery system 1 is referred to as the "base side" of that member. In addition, the direction in which the axis of the delivery system 1 and each member extends is referred to as the "axial direction", the direction perpendicular to the axis is referred to as the "radial direction", and the direction around the axis is referred to as the "circumferential direction".

[0016] The inner catheter 2, the outer catheter 4 and the tube stent 6 are each a tubular member having a single lumen structure. In this embodiment, the tube stent 6 is bent at the base end side when there is no external input (see FIG. 4(A)), and the inner catheter 2 inserted into the tube stent 6 is also bent in accordance with the bending of the tube stent 6. However, for the sake of convenience, FIG. 1 shows the tube stent 6 and the inner catheter 2 extending in a straight line.

[0017] A guide wire GW is passed through the inner catheter 2 (see FIG. 6). The inner catheter 2 is passed through the outer catheter 4 and the tube stent 6. The tube stent 6 is disposed closer to the tip of the inner catheter 2 than the outer catheter 4. In addition, an annular connection connector 8 is disposed on the base end side of the inner catheter 2, connecting the inner catheter 2 and the outer catheter 4 to each other. A portion of the base end side of the outer catheter 4 is covered with an insertion protection tube 10. The inner catheter 2 and the outer catheter 4 are connected by the connection connector 8, and the inner catheter 2 protrudes from the tip of the tube stent 6 with the base end of the tube stent 6 in contact with the tip of the outer catheter 4.

[0018] Fig. 2(A) is a side view of the inner catheter 2. Fig. 2(B) is a cross-sectional view taken along line AA in Fig. 2(A). The inner catheter 2 has a length of, for example, about 1500 to 3000 mm, an outer diameter of, for example, about 1.5 to 2.0 mm, and an inner diameter of, for example, about 1.0 to 1.5 mm. The inner catheter 2 has a first lumen 12 through which a guidewire GW is passed. The first lumen 12 is defined by the inner surface of a tube constituting the inner catheter 2, and the internal space of the tube becomes the first lumen 12.

[0019] A radiopaque marker 14 is disposed at the tip of the inner catheter 2. A visual marker 16 is disposed at the middle of the inner catheter 2. An inner connector 18 is disposed at the base end of the inner catheter 2.

[0020] Fig. 3(A) is a side view of the outer catheter 4. Fig. 3(B) is a cross-sectional view taken along line BB in Fig. 3(A). The outer catheter 4 has a length of, for example, about 1300 to 2500 mm, an outer diameter of, for example, about 2.3 to 3.0 mm, and an inner diameter of, for example, about 1.6 to 2.5 mm. The outer catheter 4 has a second lumen 20 through which the inner catheter 2 is passed. The second lumen 20 is defined by the inner surface of a tube constituting the outer catheter 4, and the internal space of the tube serves as the second lumen 20.

[0021] A radiopaque marker 22 is disposed at the tip of the outer catheter 4. An outer connector 24 is disposed at the base end of the outer catheter 4. The outer connector 24 has a recess on its base end surface, into which the inner connector 18 is inserted. In this state, the inner connector 18 and the outer connector 24 are connected to each other by a connecting connector 8. The connecting connector 8 can switch between a state in which the inner catheter 2 and the outer catheter 4 are connected to each other and a state in which they are separated from each other. In addition, a side hole 26 is disposed in the side wall of the outer catheter 4 on the tip side of the radiopaque marker 22.

[0022] FIG. 4(A) is a side view of the tube stent 6. FIG. 4(B) is a cross-sectional view taken along line CC in FIG. 4(A). The tube stent 6 has a length of, for example, about 50 to 300 mm, an outer diameter of, for example, about 2.3 to 3.0 mm, and an inner diameter of, for example, about 1.6 to 2.5 mm. The tube stent 6 has a third lumen 28 through which the inner catheter 2 is passed. The tube stent 6 also has an inner layer 30 that faces the outer surface of the inner catheter 2, and an outer layer 32 that covers the outer surface of the inner layer 30. The third lumen 28 is defined by the inner surface of the two-layer tube that constitutes the inner layer 30 and the outer layer 32, in other words, the inner surface of the inner layer 30, and the internal space of the tube or the inner layer 30 serves as the third lumen 28.

[0023] The tube stent 6 has flaps 34 on the distal and proximal sides. The distal flap 34 has a distal end connected to the side wall of the tube stent 6, and is warped away from the side wall of the tube stent 6 toward the proximal side. The proximal flap 34 has a proximal end connected to the side wall of the tube stent 6, and is warped away from the side wall of the tube stent 6 toward the distal side. At the position where each flap 34 is provided, the inside and outside of the tube stent 6 are connected to each other, and the third lumen 28 is opened to the outside. As an example, the flap 34 is formed by cutting the side wall of the tube stent 6.

[0024] In addition, a side hole 36 is arranged in the side wall of the tube stent 6 on the proximal side of the proximal flap 34. As shown in FIG. 1, a connecting string 38 is passed through the side hole 26 of the outer catheter 4 and the side hole 36 of the tube stent 6, thereby connecting the outer catheter 4 and the tube stent 6 to each other. The connecting string 38 is also tied to the inner catheter 2. In the delivery system 1 of this embodiment, as an example, the connection between the outer catheter 4 and the tube stent 6 by the connecting string 38 can be released by pulling out the inner catheter 2 from the tube stent 6. Note that the structure for connecting the outer catheter 4 and the tube stent 6 and the structure for releasing the connection are not particularly limited, and known structures can be adopted.

[0025] FIG. 5 is a schematic diagram showing a state in which the tube stent 6 is used. The delivery system 1 of this embodiment is used to deliver the tube stent 6 to a target site in the body for drainage. Examples of drainage include bile duct drainage and pancreatic duct drainage, in which case the delivery system 1 delivers the tube stent 6 to the bile duct or pancreatic duct. In the delivery system 1 before the tube stent 6 is separated, the outer catheter 4 and the tube stent 6 are arranged in this order from the base end side, and the inner catheter 2 is passed through the second lumen 20 of the outer catheter 4 and the third lumen 28 of the tube stent 6. In this state, the inner catheter 2 and the outer catheter 4 are connected by a connection connector 8. In addition, the inner catheter 2, the outer catheter 4, and the tube stent 6 are connected by a connecting string 38.

[0026] For example, in the case of bile duct drainage, the guide wire GW inserted in the bile duct 42 is passed through the first lumen 12 of the inner catheter 2. The delivery system 1 is sent from the duodenum 40 to the papilla 44 of the bile duct 42 through the endoscope along the guide wire GW. A stenosis 46 that inhibits the discharge of bile is present in the bile duct 42. When the delivery system 1 reaches the papilla 44, the inner catheter 2 is inserted into the bile duct 42 until it passes through the stenosis 46. Then, the connection between the inner catheter 2 and the outer catheter 4 by the connector 8 is released, and the tube stent 6 is sent deep into the bile duct 42 by operating the outer catheter 4. The tube stent 6 is inserted into the bile duct 42 until the flap 34 on the tip side passes through the stenosis 46. The flap 34 on the base side is placed in the duodenum 40.

[0027] After the tube stent 6 is placed at the target site, the guide wire GW is pulled out from the inner catheter 2. Also, the inner catheter 2 is pulled out from the tube stent 6. By pulling out the inner catheter 2, the connection between the outer catheter 4 and the tube stent 6 by the connecting string 38 is released. This leaves only the tube stent 6 in the bile duct 42, and the inner catheter 2 and the outer catheter 4 can be pulled out from the bile duct 42.

[0028] The placed tube stent 6 is prevented from falling out of the bile duct 42 by the flap 34 on the distal end side being caught on the stricture 46. In addition, the flap 34 on the proximal end side being caught on the papilla 44, preventing the entire stent 6 from advancing deeper than the stricture 46. The delivery procedure of the tube stent 6 in the delivery system 1 and the mechanism for placing the tube stent 6 at the target site are publicly known, so further detailed explanation will be omitted.

[0029] 6 is a cross-sectional view of the tube stent delivery system 1 and the guide wire GW. In FIG. 6, a cross section along the axial direction of the delivery system 1 is shown.

[0030] The guidewire GW has a core wire 48 and a coating 50 covering the surface of the core wire 48. The core wire 48 is made of a biocompatible metal including tungsten, stainless steel, nickel titanium, etc. The coating 50 is made of a material including polytetrafluoroethylene (PTFE). Preferably, the coating 50 is made of only PTFE.

[0031] The inner catheter 2 is made of a material containing an olefin resin (PO), for example. The PO is not particularly limited as long as it has a skeleton derived from an olefin monomer, and may be a homopolymer or a copolymer such as a random copolymer or a block copolymer. Preferred examples of PO include polyethylene (PE); polypropylene (PP); and polymethylpentene (PMP) such as TPX (registered trademark). Preferably, the inner catheter 2 is made of only PO. The inner catheter 2 may be made of a material containing PTFE.

[0032] The outer catheter 4 is made of a material containing PTFE, and preferably, the outer catheter 4 is made of only PTFE.

[0033] The inner layer 30 of the tube stent 6 is made of a material containing PTFE. Preferably, the inner layer 30 is made of only PTFE. The material constituting the outer layer 32 of the tube stent 6 is not particularly limited as long as it has a lower hardness (e.g., Shore D hardness) when the tube stent 6 is placed in the body than the material constituting the inner layer 30, but preferably, the outer layer 32 is made of a material containing polyurethane (PU). A preferred example of PU is thermoplastic polyurethane (TPU). As an example, the material constituting the outer layer 32 has a lower hardness at 37°C than the material constituting the inner layer 30. Preferably, the outer layer 32 is made of only PU. The inner layer 30 and the outer layer 32 are fixed, for example, by adhesion.

[0034] PTFE is known as a material with high slidability (smoothness). In a typical guidewire GW, the core wire 48 is covered with a coating 50 containing PTFE to improve the slidability relative to the inner catheter 2. This can improve the ease of insertion and removal of the guidewire GW relative to the inner catheter 2, and the ease of insertion and removal of the inner catheter 2 relative to the guidewire GW.

[0035] In addition, the outer catheter 4 of this embodiment is made of a resin containing PTFE, so that the outer surface has improved sliding properties against the lumen of the endoscope and the digestive tract of the human body, and the inner surface has improved sliding properties against the inner catheter 2.

[0036] In addition, the tube stent 6 of this embodiment has improved sliding properties relative to the inner catheter 2 by covering the inner surface of the outer layer 32 with the inner layer 30 containing PTFE. The inner layer 30 containing PTFE can also prevent bile and pancreatic juice, which are the drainage targets, from adhering to the wall surface of the third lumen 28, thereby preventing drainage from being impeded. The outer layer 32 containing PU can also impart appropriate flexibility to the tube stent 6. This makes it easier for the shape of the tube stent 6 to follow the shape of the endoscope and the target site. In addition, sliding properties relative to the lumen of the endoscope and the digestive tract of the human body are also maintained.

[0037] Furthermore, by forming the inner layer 30 from a material containing PTFE and the outer layer 32 from a material containing PU, it is possible to make the tube stent 6 less susceptible to deterioration. Furthermore, by laminating the inner layer 30, which has a relatively high hardness when placed in the body, on the outer layer 32, which has a relatively low hardness when placed in the body, it is possible to suppress damage to the flap 34.

[0038] Moreover, the strength of the inner layer 30 per unit area when stretched 50% in the axial direction of the tube stent 6 is lower than the strength of the outer catheter 4 per unit area when stretched 50% in the axial direction of the outer catheter 4. The axial directions of the tube stent 6 and the outer catheter 4 are equal to the axial direction of the delivery system 1. The strength at 50% stretch in this embodiment is the strength measured by a tensile test described below, and is the force applied per unit area of ​​the test piece when the test piece cut out from each of the inner layer 30 and the outer catheter 4 is stretched 50%, that is, when the test piece becomes 150% long. The strength of the inner layer 30 at 50% stretch in the axial direction is, for example, 5 MPa or more and 20 MPa or less. The strength of the outer catheter 4 at 50% stretch in the axial direction is, for example, 20 MPa or more and 80 MPa or less.

[0039] The tensile test is performed in accordance with Annex B (Method of measurement of breaking strength) of ISO10555-1:2013 (Intravascular catheters-Sterile and single-use catheters-) under the conditions of a test piece length (distance between chucks) of 25 mm and a tensile speed of 500 mm / min (procedure B.3.2 of Annex B is not performed). Therefore, the strength is measured when the test piece is elongated by 12.5 mm to 37.5 mm.

[0040] By making the strength of the inner layer 30 per unit area in the axial direction when stretched 50% lower than the strength of the outer catheter 4 per unit area in the axial direction when stretched 50%, the inner layer 30 can be made to more easily follow the deformation of the outer layer 32. This makes it possible to make the inner layer 30 and the outer layer 32 less likely to peel off from each other. In other words, peeling between the inner layer 30 and the outer layer 32 can be suppressed.

[0041] Furthermore, the degree of molecular orientation of the inner layer 30 in the axial direction of the tube stent 6 is lower than the degree of molecular orientation of the outer catheter 4 in the axial direction of the outer catheter 4. When the inner layer 30 and the outer catheter 4 are each made of PTFE, the degree of molecular orientation of the PTFE contained in the inner layer 30 in the axial direction is lower than the degree of molecular orientation of the PTFE contained in the outer catheter 4 in the axial direction. In other words, the orientation of the PTFE fibers in the outer catheter 4 is more along the axial direction than the orientation of the PTFE fibers in the inner layer 30.

[0042] By making the degree of molecular orientation of the inner layer 30 in the axial direction lower than the degree of molecular orientation of the outer catheter 4 in the axial direction, the strength of the inner layer 30 when stretched 50% in the axial direction can be made lower than the strength of the outer catheter 4 when stretched 50% in the axial direction. This makes it easier for the inner layer 30 to follow the deformation of the outer layer 32, and makes it possible to suppress peeling between the inner layer 30 and the outer layer 32.

[0043] The degree of molecular orientation of the inner layer 30 and the outer catheter 4 can be determined by measuring the birefringence of the inner layer 30 and the outer catheter 4. The birefringence is expressed by the following formula (1). ΔN=Re / t (1) In formula (1), ΔN is birefringence, Re is retardation, and t is the thickness of the test sample. Retardation is the phase difference caused by the refractive index difference of the test sample when the measurement light passes through the test sample sandwiched between two polarizing plates.

[0044] Generally, the molecular orientation of a resin molded product is produced by the flow and deformation of the resin during the molding process. The molecular orientation causes anisotropy in various properties of the resin molded product. An example of a property that causes anisotropy is the refractive index related to optical anisotropy. The difference between two different refractive indices measured in a resin molded product having optical anisotropy is defined as birefringence. In other words, birefringence represents the difference in refractive index between a predetermined first direction and a second direction perpendicular to the first direction. This difference in refractive index corresponds to the difference in the magnitude of molecular orientation. Generally, when the refractive index in the first direction is larger than the refractive index in the second direction, the birefringence is large. A large birefringence indicates that the molecular orientation in the first direction is larger than the molecular orientation in the second direction, that is, the degree of molecular orientation in the first direction is high.

[0045] In this embodiment, the birefringence of the inner layer 30 is the difference between the refractive index in the axial direction (first direction) of the tube stent 6 and the refractive index in the radial direction (second direction) of the tube stent 6. The birefringence of the outer catheter 4 is the difference between the refractive index in the axial direction (first direction) of the outer catheter 4 and the refractive index in the radial direction (second direction) of the tube stent 6. The birefringence of the inner layer 30 is, for example, 1×10 -4 More than 1×10 -3 The birefringence of the outer catheter 4 is, for example, 1×10 -3 More than 2×10 -2 The following is the result.

[0046] Preferably, the thickness of the inner layer 30 is thinner than the thickness of the outer layer 32. This allows the inner layer 30 to more easily follow the deformation of the outer layer 32, and therefore peeling of the inner layer 30 and the outer layer 32 from each other can be more effectively prevented. The thickness of the inner layer 30 is preferably 50 μm or less. By setting the thickness of the inner layer 30 to 50 μm or less, the rigidity of the inner layer 30 can be reduced, and the inner layer 30 can more easily follow the deformation of the outer layer 32. The thickness of the inner layer 30 may be 30 μm or less, or 20 μm or less.

[0047] Moreover, the thickness of the outer catheter 4 is preferably more than 10 times the thickness of the inner layer 30 (therefore, the thickness of the inner layer 30 is 1 / 10 or less of the thickness of the outer catheter 4), for example, about 0.2 to 0.5 mm. By making the thickness of the outer catheter 4 more than 10 times the thickness of the inner layer 30, it is possible to impart appropriate rigidity to the outer catheter 4. This makes it possible to prevent the outer catheter 4 from breaking when the inner catheter 2 is displaced relative to the outer catheter 4. It also makes it easier to adjust the position of the tube stent 6.

[0048] It is desirable that the inner layer 30 has a certain degree of rigidity from the viewpoint of suppressing damage to the flap 34. It is desirable that the outer catheter 4 has a certain degree of rigidity from the viewpoint of suppressing deformation when the inner catheter 2 is inserted and removed. On the other hand, as the rigidity of the inner layer 30 and the outer catheter 4 increases, the sliding resistance between the inner layer 30 and the outer catheter 4 and the inner catheter 2 tends to increase. In other words, various factors are involved in determining the rigidity of the inner layer 30 and the outer catheter 4. For this reason, it should not be deemed that a person skilled in the art could easily set the strength and molecular orientation of the inner layer 30 at 50% stretch to be lower than the strength and molecular orientation of the outer catheter 4 at 50% stretch.

[0049] (Method of manufacturing tube stent delivery system 1) There is no particular limitation on the method for forming the inner catheter 2. For example, the inner catheter 2 is formed by extrusion molding a paste of a material containing PO. The X-ray opaque marker 14, the visual marker 16, and the inner connector 18 are attached to the obtained inner catheter 2.

[0050] The outer catheter 4 is formed by paste extrusion molding a material containing PTFE fine powder. By paste extrusion molding a material containing PTFE fine powder, it is possible to easily orient the PTFE fibers in the axial direction. This can increase the strength of the outer catheter 4 when it is stretched 50% in the axial direction. Preferably, the outer catheter 4 is formed by paste extrusion molding in a hollow state. In paste extrusion molding, a material is generally extruded vertically downward. In paste extrusion molding in a hollow state, unlike paste extrusion molding on the outer peripheral surface of a mandrel, the extruded material (outer catheter 4) is pulled downward by its own weight. This can make it possible to orient the PTFE fibers more axially. Therefore, it is possible to further increase the strength of the outer catheter 4 when it is stretched 50% in the axial direction. The obtained outer catheter 4 is attached with the X-ray opaque marker 22, the outer connector 24, and the insertion protection tube 10, and is provided with a side hole 26.

[0051] The inner layer 30 is formed by coating a dispersion of a material containing PTFE. In coating, for example, the dispersion is applied to the outer peripheral surface of a mandrel to form the inner layer 30. In coating, the PTFE fibers are less likely to be oriented in the axial direction compared to extrusion. This makes it easier to impart to the inner layer 30 a strength at 50% stretch that is lower than that of the outer catheter 4.

[0052] The method of forming the outer layer 32 is not particularly limited. For example, the outer layer 32 is formed by extruding pellets of a material containing PU. The inner layer 30 and the outer layer 32 are then fixed to each other to form the tube stent 6. As an example, the outer surface of the inner layer 30 is etched, and the outer layer 32 is extruded against this outer surface to fix the inner layer 30 and the outer layer 32 to each other. Alternatively, the inner layer 30 and the outer layer 32 are laminated and then reflowed (melted) to bond the two layers, thereby fixing the inner layer 30 and the outer layer 32 to each other. The obtained tube stent 6 is provided with flaps 34 and side holes 36.

[0053] The inner catheter 2 is passed through the outer catheter 4 and the tube stent 6. These are then connected to each other by a connecting cord 38. The inner catheter 2 and the outer catheter 4 are also connected to each other by a connector 8. Through the above steps, the delivery system 1 is obtained.

[0054] The above describes the embodiments of the present disclosure in detail. The above-mentioned embodiments merely show specific examples of implementing the present disclosure. The contents of the embodiments do not limit the technical scope of the present disclosure, and many design changes such as changes, additions, and deletions of components are possible within the scope of the idea of ​​the present disclosure defined in the claims. A new embodiment with a design change has the effects of each of the combined embodiments and modifications. In the above-mentioned embodiments, the contents for which such design changes are possible are emphasized by adding notations such as "in this embodiment" and "in this embodiment", but design changes are permitted even in contents without such notations. Any combination of components included in each embodiment is also valid as an aspect of the present disclosure. The hatching on the cross section of the drawing does not limit the material of the object to which the hatching is added.

[0055] The embodiment may be specified by the items described below. [1st item] an inner catheter (2) having a first lumen (12) through which a guidewire (GW) is passed; an outer catheter (4) having a second lumen (20) through which the inner catheter (2) is passed; a tube stent (6) having a third lumen (28) through which the inner catheter (2) is passed and disposed closer to the tip end of the inner catheter (2) than the outer catheter (4); The outer catheter (4) is made of a material including polytetrafluoroethylene, The tube stent (6) has an inner layer (30) made of a material containing polytetrafluoroethylene and defining a third lumen (28), and an outer layer (32) covering the inner layer (30); the strength of the inner layer (30) per unit area in the axial direction of the tube stent (6) when stretched 50% is lower than the strength of the outer catheter (4) per unit area in the axial direction of the outer catheter (4) when stretched 50%; Tube stent delivery system (1). [Second item] an inner catheter (2) having a first lumen (12) through which a guidewire (GW) is passed; an outer catheter (4) having a second lumen (20) through which the inner catheter (2) is passed; a tube stent (6) having a third lumen (28) through which the inner catheter (2) is passed and disposed closer to the tip end of the inner catheter (2) than the outer catheter (4); The outer catheter (4) is made of a material including polytetrafluoroethylene, The tube stent (6) has an inner layer (30) made of a material containing polytetrafluoroethylene and defining a third lumen (28), and an outer layer (32) covering the inner layer (30); the degree of molecular orientation of the inner layer (30) in the axial direction of the tube stent (6) is lower than the degree of molecular orientation of the outer catheter (4) in the axial direction of the outer catheter (4); Tube stent delivery system (1). [3rd item] The thickness of the inner layer (30) is 50 μm or less. A tube stent delivery system (1) according to item 1 or 2. [4th item] The outer layer (32) is composed of a material including polyurethane. A tube stent delivery system (1) according to any one of items 1 to 3. [Item 5] A method for manufacturing a tube stent delivery system (1) including an inner catheter (2) having a first lumen (12) through which a guide wire (GW) is passed, an outer catheter (4) having a second lumen (20) through which the inner catheter (2) is passed, and a tube stent (6) having a third lumen (28) through which the inner catheter (2) is passed and disposed on the distal end side of the inner catheter (2) relative to the outer catheter (4), comprising: The tube stent (6) has an inner layer (30) made of a material containing polytetrafluoroethylene and defining a third lumen (28), and an outer layer (32) covering the inner layer (30); The manufacturing method includes forming an outer catheter (4) by extruding a paste of a material containing polytetrafluoroethylene, and forming an inner layer (30) by applying a dispersion of a material containing polytetrafluoroethylene. A method for manufacturing a tubular stent delivery system (1). [Item 6] The outer catheter (4) is formed by hollow extrusion molding of a paste. A method for manufacturing the tube stent delivery system (1) described in item 5. [Explanation of symbols]

[0056] 1 tubular stent delivery system, 2 inner catheter, 4 outer catheter, 6 tubular stent, 12 first lumen, 20 second lumen, 28 third lumen, 30 inner layer, 32 outer layer, GW guidewire.

Claims

1. an inner catheter having a first lumen through which a guidewire is passed; an outer catheter having a second lumen through which the inner catheter is passed; a tube stent having a third lumen through which the inner catheter is passed and disposed on the distal end side of the inner catheter relative to the outer catheter; the outer catheter is made of a material including polytetrafluoroethylene; The tube stent has an inner layer made of a material containing polytetrafluoroethylene and defining the third lumen, and an outer layer covering the inner layer, The strength of the inner layer per unit area when stretched by 50% in the axial direction of the tube stent is lower than the strength of the outer catheter per unit area when stretched by 50% in the axial direction of the outer catheter. Tube stent delivery system.

2. an inner catheter having a first lumen through which a guidewire is passed; an outer catheter having a second lumen through which the inner catheter is passed; a tube stent having a third lumen through which the inner catheter is passed and disposed on the distal end side of the inner catheter relative to the outer catheter; the outer catheter is made of a material including polytetrafluoroethylene; The tube stent has an inner layer made of a material containing polytetrafluoroethylene and defining the third lumen, and an outer layer covering the inner layer, The molecular orientation of the inner layer in the axial direction of the tube stent is lower than the molecular orientation of the outer catheter in the axial direction of the outer catheter. Tube stent delivery system.

3. The thickness of the inner layer is 50 μm or less. A tube stent delivery system as claimed in claim 1 or 2.

4. The outer layer is made of a material including polyurethane. A tube stent delivery system as claimed in claim 1 or 2.

5. A method for manufacturing a tube stent delivery system comprising an inner catheter having a first lumen through which a guidewire is passed, an outer catheter having a second lumen through which the inner catheter is passed, and a tube stent having a third lumen through which the inner catheter is passed and disposed on a distal end side of the inner catheter relative to the outer catheter, comprising: The tube stent has an inner layer made of a material containing polytetrafluoroethylene and defining the third lumen, and an outer layer covering the inner layer, The manufacturing method includes forming the outer catheter by extruding a paste of a material containing polytetrafluoroethylene, and forming the inner layer by applying a dispersion of a material containing polytetrafluoroethylene. A method for manufacturing a tube stent delivery system.

6. The outer catheter is formed by hollow extrusion molding of the paste. A method for manufacturing the tube stent delivery system according to claim 5.

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