Tube stent delivery system

Abstract

To improve operability of a tube stent delivery system 1.SOLUTION: A tube stent delivery system 1 includes: an inner catheter 2 into which a guide wire GM having a film 50 composed of a material containing PTFE 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 inner catheter 2 is composed of a material containing PO. The tube stent 6 includes an inner layer 30 composed of a material containing PTFE and opposed to the inner catheter 2 and an outer layer 32 for covering the inner layer 30.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates to a 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 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] In a tube stent delivery system, the guidewire, guide catheter, indwelling tube, and pusher tube each slide relative to one of the other members when the delivery system is inserted into the body along the guidewire, when the indwelling tube is placed in a stricture, etc. For this reason, it is desirable to improve the operability of the tube stent delivery system by increasing the slidability of each member.

[0005] The present disclosure has been made in consideration of these circumstances, and its purpose is to provide a technique for improving the operability of a tube stent delivery system. [Means for solving the problem]

[0006] One 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 having a coating made of a material containing polytetrafluoroethylene 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 inner catheter is made of a material containing an olefin resin. The tube stent has an inner layer made of a material containing polytetrafluoroethylene that faces the inner catheter, and an outer layer that covers the inner layer.

[0007] 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

[0008] According to the present disclosure, the operability of a tube stent delivery system can be improved. [Brief description of the drawings]

[0009] [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

[0010] 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.

[0011] 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.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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. 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.

[0016] 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.

[0017] 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. 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.

[0018] 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.

[0019] Fig. 4(A) is a side view of a 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. 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, and the internal space of the tube serves as the third lumen 28.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] The inner catheter 2 is made of a material containing an olefin resin (PO). 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.

[0029] Although there are no particular limitations on the material that constitutes the outer catheter 4, the outer catheter 4 is preferably made of a material containing PTFE, and more preferably, the outer catheter 4 is made of only PTFE.

[0030] 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, but preferably, the outer layer 32 is made of a material containing polyurethane (PU). A preferred example of PU is thermoplastic polyurethane (TPU). 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. The tube stent delivery system 1 can be manufactured using a known molding method or the like.

[0031] 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.

[0032] 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.

[0033] 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 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. In addition, sliding properties relative to the lumen of the endoscope and the digestive tract of the human body are maintained.

[0034] In addition, by forming the inner layer 30 from a material containing PTFE and forming the outer layer 32 from a material containing PU, the tube stent 6 can be made less susceptible to deterioration. In addition, by laminating the inner layer 30, which has a relatively high hardness, on the outer layer 32, which has a relatively low hardness, damage to the flap 34 can be suppressed. 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 easily follow the deformation of the outer layer 32, and therefore peeling of the inner layer 30 from the outer layer 32 can be suppressed.

[0035] The inner catheter 2 of this embodiment is made of a material containing PO. The inner surface of the inner catheter 2 slides against the guidewire GW, and the outer surface of the inner catheter 2 slides against the outer catheter 4 and the tube stent 6. Therefore, in order to improve the slidability against other members, it is generally considered to make the inner catheter 2 from a material containing PTFE, PVDF, etc.

[0036] In response to this, the present inventors conducted extensive research and found that, when the inner catheter 2 is made of PTFE or PVDF, the slidability against the coating 50 of the guidewire GW, the outer catheter 4, and the inner layer 30 of the tube stent 6, all of which are made of PTFE, is reduced compared to when the inner catheter 2 is made of PO. This is presumably due to the fact that PTFE and PVDF have high electronegativity and are easily negatively charged, whereas the air present between the inner catheter 2 and the sliding counterpart has low electronegativity and is easily positively charged.

[0037] In other words, when the inner catheter 2 is made of PTFE or PVDF and the sliding counterpart is made of PTFE, each of them strongly attracts the air between them, which results in a decrease in their sliding properties. In contrast, by making the inner catheter 2 out of a material containing PO, which has a lower electronegativity and is less resistant to electricity than PTFE or PVDF, the force of attraction between the inner catheter 2 and the air can be weakened. As a result, the sliding properties between the inner catheter 2 and the sliding counterpart can be improved. This can improve the operability of the delivery system 1.

[0038] It is desirable for the inner catheter 2 to have an appropriate rigidity so that it can break through the stricture 46 when inserted into the bile duct 42. In contrast, the inner catheter 2 of this embodiment has a three-point bending strength of 2.5 N or more, measured by a three-point bending test under the following measurement conditions. More preferably, the inner catheter 2 has a three-point bending strength of 4.0 N or more. Therefore, it is preferable that the material constituting the inner catheter 2 contains high density polyethylene (HDPE), high molecular weight PP, or high molecular weight PMP.

[0039] The measurement conditions for the three-point bending test are as follows. That is, the middle part of the inner catheter 2 is supported by the first support point and the second support point 30 mm away from the first support point. The middle part of the inner catheter 2 is the part near the tip of the tube stent 6 when the tube stent 6 and the inner catheter 2 are extended in a straight line as shown in FIG. 1, and is, for example, the part overlapping with the tip of the tube stent 6. The temperature is 24°C (room temperature). The probe is pressed against the middle point between the first support point and the second support point. The contact length between the probe and the inner catheter 2 is 7 mm. The pushing speed is 10 mm / min. The pushing amount after the reaction force is detected is 3 mm. When the inner catheter 2 is pushed in by the probe, the inner catheter 2 is fixed at the first support point and the second support point so that it is not pulled in.

[0040] 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.

[0041] The embodiment may be specified by the items described below. [1st item] an inner catheter (2) having a first lumen (12), through which a guide wire (GW) having a coating (50) made of a material including polytetrafluoroethylene 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 inner catheter (2) is made of a material containing an olefin-based resin, The tube stent (6) has an inner layer (30) made of a material containing polytetrafluoroethylene and facing the inner catheter (2), and an outer layer (32) covering the inner layer (30). Tube stent delivery system (1). [Second item] The inner catheter (2) has a three-point bending strength of 2.5 N or more as measured by a three-point bending test in which a probe is pressed between two support points with a distance of 30 mm between the support points at a temperature of 24°C, a pushing speed of 10 mm / min, and a pushing depth of 3 mm. Item 1. A tube stent delivery system (1). [3rd item] The outer catheter (4) is made of a material including polytetrafluoroethylene. 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. [Explanation of symbols]

[0042] 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, 50 coating, GW guidewire.

Claims

1. an inner catheter having a first lumen through which a guide wire having a coating made of a material including polytetrafluoroethylene 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 inner catheter is made of a material containing an olefin-based resin, The tube stent has an inner layer made of a material containing polytetrafluoroethylene and facing the inner catheter, and an outer layer covering the inner layer. Tube stent delivery system.

2. The inner catheter has a three-point bending strength of 2.5 N or more as measured by a three-point bending test in which a probe is pressed between two support points with a distance of 30 mm between the support points at a temperature of 24° C., a pushing speed of 10 mm / min, and a pushing depth of 3 mm.

2. The tube stent delivery system of claim 1.

3. The outer catheter is made of a material including polytetrafluoroethylene. 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.

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