In-vivo indwelling tool

Abstract

To provide an in-vivo indwelling tool which self-expands easily and thereby obtains a suitable expanded area in a short period.SOLUTION: An in-vivo indwelling tool 1 has: a stent 2; and a tubular body 10 which is fixed on a proximal end side of a distal end 2D of the stent 2 and on a distal end side of a proximal end 2P of the stent 2, and extends in a radial direction y with the expansion of the stent 2. The stent 2 has: a distal stent part 3 at a position from the distal end 2D of the stent 2 to a distal end 10D of the tubular body 10; and a proximal stent part 4 at a position from the proximal end 2P of the stent 2 to a proximal end 10P of the tubular body 10 in a longitudinal direction x. In the longitudinal direction x, the total sum of a length L1 of the distal stent part 3 and a length L2 of the proximal stent part 4 is 1 / 2 or more of a length L3 of the tubular body 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an in-vivo indwelling device to be placed in a vascular diseased area. [Background technology]

[0002] Endovascular treatment is one of the treatments for vascular lesions such as head and neck aneurysms, arteriovenous malformations, arteriovenous fistulas, pulmonary vascular malformations, renal vascular malformations, renal artery aneurysms, thoracic aneurysms, abdominal aneurysms, iliac artery aneurysms, and acute aortic dissection. In endovascular treatment, an in-vivo device such as a stent graft, a flow diverter stent, or an embolization coil is placed at a target site to promote thrombosis, thereby preventing, for example, the rupture of an aneurysm. For example, Patent Documents 1 to 3 disclose stent grafts. A stent graft has a stent and a graft as a tubular body extending in the radial direction. In its longitudinal direction, the stent graft has an end portion where only the stent is disposed and a portion where the graft (tubular body) is attached to the stent. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2018-516735 [Patent Document 2] Special Publication No. 2007-508067 [Patent Document 3] Japanese Patent Publication No. 2022-24124 Summary of the Invention [Problem to be solved by the invention]

[0004] Stent grafts self-expand in vivo due to the elasticity of the stent, but a larger expansion area is required to reduce the risk of restenosis and other conditions within the stent graft. However, conventional stent grafts such as those described in Patent Documents 1 to 3 have difficulty self-expanding at the portion where the graft (tubular body) is attached to the stent, compared to the end portion where only the stent is placed. This has led to problems such as the need for time to fully expand, and the need for post-expansion using a separate device such as a balloon due to poor expansion, where the stent graft does not expand to a sufficient diameter. Therefore, an object of the present invention is to provide an in-vivo device that is easily self-expandable and can obtain an appropriate expansion area in a short period of time. [Means for solving the problem]

[0005] The in-vivo indwelling device according to the embodiment of the present invention that can solve the above problems is as follows. [1] A stent having a longitudinal axis direction and a radial direction, and having a distal end and a proximal end in the longitudinal axis direction; a tubular body having a distal end and a proximal end in the longitudinal axis direction, fixed to the stent proximally and distally of the distal end, and extending in the radial direction as the stent expands; The stent has a distal stent section extending from the distal end of the stent to the distal end of the tubular body in the longitudinal axis direction, and a proximal stent section extending from the proximal end of the stent to the proximal end of the tubular body, The in-vivo indwelling device has a total length of the distal stent portion and the proximal stent portion in the longitudinal axis direction that is equal to or greater than half the length of the tubular body.

[0006] Furthermore, the in-vivo indwelling device according to the embodiment is preferably any one of the following [2] to

[11] . [2] The in-vivo indwelling device according to [1], wherein the tubular body is not present in the distal stent portion and the proximal stent portion. [3] The in-vivo indwelling device according to [1] or [2], wherein the length of the distal stent portion and the length of the proximal stent portion in the longitudinal axis direction are each shorter than the length of the tubular body. [4] The in-vivo indwelling device according to any one of [1] to [3], wherein the distal stent portion is longer than the proximal stent portion in the longitudinal axis direction. [5] The in-vivo indwelling device according to any one of [1] to [4], wherein the stent is tubular and has a circumferential direction, and a first arrangement pattern repeated in the circumferential direction is arranged in a plurality of rows in the longitudinal axis direction, and the distal stent portion and the proximal stent portion each have three or more of the first arrangement patterns. [6] The in-vivo indwelling device according to any one of [1] to [5], further comprising a radiopaque marker disposed at least at either the distal end or the proximal end of the tubular body. [7] The in-vivo indwelling device according to any one of [1] to [6], further comprising a radiopaque marker disposed in at least one of the distal stent portion and the proximal stent portion. [8] The in-vivo indwelling device according to any one of [1] to [7], wherein the tubular body has a radial direction, and when the thickness of the tubular body is divided into two equal parts in the radial direction into an inner part and an outer part, the in-vivo indwelling device further has a radiopaque marker disposed in the inner part. [9] The in-vivo indwelling device according to any one of [1] to [8], wherein the material constituting the tubular body includes at least one selected from polyester, polyethylene terephthalate, polytetrafluoroethylene, polyurethane, polyacrylonitrile, polyamide, polylactic acid, polyglycolic acid, polyhydroxybutyrate, chitosan, and collagen.

[10] The in-vivo indwelling device according to any one of [1] to [9], wherein particles made of a radiopaque material are present within the tubular body.

[11] The in-vivo indwelling device according to any one of [1] to

[10] , which is for treating cerebral aneurysms. [Effects of the Invention]

[0007] In the in-vivo indwelling device, the tubular body is provided with a distal stent section and a proximal stent section, and the total length of these stent sections is at least half the length of the tubular body, so that the self-expansion of the distal stent section and the proximal stent section promotes the self-expansion of the tubular body sandwiched between the distal stent section and the proximal stent section. Therefore, an in-vivo indwelling device that is easy to self-expand and can obtain an appropriate expansion area in a short period of time can be provided. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a side view of an in-vivo indwelling device according to one embodiment of the present invention. [Figure 2] FIG. 2 is a side view showing a modified example of the in-vivo indwelling device shown in FIG. [Figure 3] 1. FIG. 4 is a side view showing another modified example of the in-vivo indwelling device shown in FIG. [Figure 4] FIG. 10 is a side view showing yet another modified example of the in-vivo indwelling device shown in FIG. [Figure 5] FIG. 2 is an end view of a section perpendicular to the longitudinal axis direction of the in-vivo indwelling device shown in FIG. [Figure 6] FIG. 10 is a side view showing yet another modified example of the in-vivo indwelling device shown in FIG. [Figure 7] FIG. 7 is an end view of a section perpendicular to the longitudinal axis direction of the in-vivo indwelling device shown in FIG. 6. [Figure 8] FIG. 8 is a cross-sectional end view showing a modified example of the in-vivo indwelling device shown in FIG. [Figure 9] FIG. 10 is a side view showing yet another modified example of the in-vivo indwelling device shown in FIG. [Figure 10] FIG. 10 is an end view of a section perpendicular to the longitudinal axis direction of the in-vivo indwelling device shown in FIG. [Figure 11] FIG. 11 is a cross-sectional end view showing a modified example of the in-vivo indwelling device shown in FIG. [Figure 12] FIG. 10 is a side view showing yet another modified example of the in-vivo indwelling device shown in FIG. [Figure 13] FIG. 13 shows a modified example of the in-vivo indwelling device shown in FIG. 12, and is an end view of a cross section perpendicular to the longitudinal axis direction of the in-vivo indwelling device. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will be described in more detail below based on the following embodiments. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the above and below-described purposes, and all such modifications are included within the technical scope of the present invention. For convenience, hatching and component symbols may be omitted in the drawings. In such cases, reference should be made to the specification or other drawings. The dimensions of various components in the drawings may differ from actual dimensions, as priority is given to helping understand the features of the present invention.

[0010] An in-vivo indwelling device in one embodiment of the present invention comprises: a stent having a longitudinal axis direction and a radial direction, and having a distal end and a proximal end in the longitudinal axis direction; and a tubular body having a distal end and a proximal end in the longitudinal axis direction, fixed proximally of the distal end of the stent and distally of the proximal end of the stent, and extending radially as the stent expands, wherein the stent has a distal stent section extending from the distal end of the stent to the distal end of the tubular body in the longitudinal axis direction, and a proximal stent section extending from the proximal end of the stent to the proximal end of the tubular body, and the sum of the lengths of the distal stent section and the proximal stent section in the longitudinal axis direction is at least half the length of the tubular body. In the in-vivo indwelling device, the tubular body is provided with a distal stent section and a proximal stent section, and the total length of these stent sections is at least half the length of the tubular body, so that the self-expansion of the distal stent section and the proximal stent section promotes the self-expansion of the tubular body sandwiched between the distal stent section and the proximal stent section. Therefore, an in-vivo indwelling device that is easy to self-expand and can obtain an appropriate expansion area in a short period of time can be provided.

[0011] Hereinafter, an in-vivo indwelling device may be simply referred to as an indwelling device. An indwelling device is used inside a lumen of the body, and is placed, for example, at a lesion in a lumen of the body. Examples of uses of the indwelling device include the treatment of vascular lesions such as head and neck aneurysms, arteriovenous malformations, arteriovenous fistulas, pulmonary vascular malformations, renal vascular malformations, renal artery aneurysms, thoracic aneurysms, abdominal aneurysms, iliac artery aneurysms, and acute aortic dissection. Of these, the indwelling device is preferably used to treat cerebral aneurysms. Examples of the shape of the aneurysm include fusiform and saccular aneurysms.

[0012] An in-vivo indwelling device according to one embodiment of the present invention will be described with reference to Figs. 1 to 13. Fig. 1 is a side view of an in-vivo indwelling device according to one embodiment of the present invention. Fig. 2 is a side view showing a modified example of the in-vivo indwelling device shown in Fig. 1. Fig. 3 is a side view showing another modified example of the in-vivo indwelling device shown in Fig. 1. Fig. 4 is a side view showing yet another modified example of the in-vivo indwelling device shown in Fig. 1. Fig. 5 is a cross-sectional end view perpendicular to the longitudinal axis direction of the in-vivo indwelling device shown in Fig. 1. Fig. 6 is a side view showing yet another modified example of the in-vivo indwelling device shown in Fig. 1. Fig. 7 is a cross-sectional end view perpendicular to the longitudinal axis direction of the in-vivo indwelling device shown in Fig. 6. Fig. 8 is a cross-sectional end view showing a modified example of the in-vivo indwelling device shown in Fig. 7. Fig. 9 is a side view showing yet another modified example of the in-vivo indwelling device shown in Fig. 1. Fig. 10 is a cross-sectional end view perpendicular to the longitudinal axis direction of the in-vivo indwelling device shown in Fig. 9. Fig. 11 is a cross-sectional end view showing a modified example of the in-vivo indwelling device shown in Fig. 10. Figure 12 is a side view showing yet another modified example of the in-vivo indwelling device shown in Figure 1. Figure 13 is an end view of a cross section perpendicular to the longitudinal axis direction of the in-vivo indwelling device, showing a modified example of the in-vivo indwelling device shown in Figure 12. As shown in Figure 1, the indwelling device 1 has a stent 2 and a tubular body 10. The stent 2 has a distal stent portion 3 and a proximal stent portion 4.

[0013] As shown in FIG. 1, the stent 2 has a longitudinal axis direction x and a radial direction y, and has a distal end 2D and a proximal end 2P in the longitudinal axis direction x. The stent 2 preferably further has a circumferential direction p. The proximal side of the stent 2 refers to the direction toward the user or surgeon with respect to the longitudinal axis direction x of the stent 2, and the distal side refers to the opposite direction from the proximal side, i.e., the direction toward the treatment target. In FIG. 1, the right side of the drawing is the proximal side, and the left side of the drawing is the distal side. The radial direction y of the stent 2 refers to the radial direction of the stent 2, and the inward radial direction of the stent 2 refers to the direction toward the center of the longitudinal axis of the stent 2, and the outward radial direction y refers to the direction extending radially from the center of the longitudinal axis opposite to the inward direction. The circumferential direction p of the stent 2 refers to the direction around the longitudinal axis.

[0014] The tubular body 10 has a distal end 10D and a proximal end 10P in the longitudinal axis direction x, is fixed proximal to the distal end 2D of the stent 2 and distal to the proximal end 2P of the stent 2, and extends in the radial direction y as the stent 2 expands.

[0015] The placement of the indwelling device 1 in the body can be achieved, for example, by the following procedure: First, a guidewire is inserted into a blood vessel. A microcatheter, which serves as a delivery tube for the indwelling device 1, is inserted along the guidewire. Once the microcatheter has been guided to the location of the lesion (e.g., an aneurysm) in the blood vessel, the guidewire is removed, and a delivery device mounted with the indwelling device 1 is inserted to the location of the lesion (e.g., an aneurysm) in the blood vessel. When placed in the delivery device, the indwelling device 1 contracts in the radial direction y of the stent 2 and expands in the longitudinal direction x, resulting in a reduced-diameter state that is more elongated and cylindrical than the expanded state. At this time, the tubular body 10 is positioned so as to straddle the aneurysm. When the indwelling device 1 is exposed from the delivery device, the stent 2 expands, fixing the indwelling device 1 to the blood vessel, and the tubular body 10 forms an artificial blood vessel. When the indwelling device 1 adheres to the blood vessel wall, blood flows through the indwelling device 1, thereby suppressing the blood inflow rate and blood flow rate into the aneurysm.

[0016] When placed in the delivery device, the indwelling device 1 contracts in the radial direction y of the stent 2 and expands in the longitudinal direction x, thereby assuming a reduced-diameter state in which it has a cylindrical shape that is thinner and longer than its expanded state. The indwelling device 1 is preferably expandable in the radial direction y from a first diameter to a second diameter. The size of the indwelling device 1 in the radial direction y is variable, and the first diameter is, for example, the diameter obtained when a compressive force is applied inward in the radial direction y of the stent 2 to contract the diameter, and the second diameter is, for example, the diameter obtained when the compressive force applied inward in the radial direction y of the stent 2 is released to expand the diameter outward in the radial direction y.

[0017] As shown in FIG. 1 , stent 2 has a distal stent section 3 extending from distal end 2D of stent 2 to distal end 10D of tubular body 10 in the longitudinal axis direction x, and a proximal stent section 4 extending from proximal end 2P of stent 2 to proximal end 10P of tubular body 10. In the longitudinal axis direction x, the sum of length L1 of distal stent section 3 and length L2 of proximal stent section 4 is equal to or greater than half of length L3 of tubular body 10. In indwelling device 1, tubular body 10 is provided with distal stent section 3 and proximal stent section 4, and the sum of the lengths of these stent sections is equal to or greater than half of tubular body length L3. This allows the self-expansion of distal stent section 3 and proximal stent section 4 to promote the self-expansion of tubular body 10 sandwiched between distal stent section 3 and proximal stent section 4. Therefore, an in-vivo indwelling device 1 can be provided that is easy to self-expand and can obtain an appropriate expansion area in a short period of time.

[0018] Each element constituting the indwelling device 1 will be further explained below.

[0019] The shape of the indwelling device 1 is not particularly limited, but it is preferably a tubular shape, and more preferably a tubular shape having only one lumen.

[0020] The stent 2 is preferably a self-expanding stent, which allows it to expand to a predetermined size by itself by removing an external member that restricts the expansion of the stent.

[0021] The stent 2 is preferably tubular, and more preferably has only one lumen.

[0022] The form of the stent 2 is not particularly limited, and examples thereof include (a) a coiled stent made of a single linear metal and / or polymer material, (b) a stent processed by cutting a metal tube or a polymer material tube with a laser, (c) a stent assembled by welding linear members with a laser, and (d) a stent made by weaving or knitting multiple linear metals, among which form (d) is preferred. The specific structure of the stent will be described later.

[0023] The stent 2 preferably has a mesh structure. The mesh structure preferably has a plurality of meshes 8. The plurality of meshes 8 are preferably aligned in the longitudinal axis direction x. Also, the plurality of meshes 8 are preferably aligned in the circumferential direction p. Although not shown, the stent 2 may have a plurality of cells and links connecting adjacent cells.

[0024] As shown in FIG. 1, the stent 2 may have a central stent section 5 located between the distal stent section 3 and the proximal stent section 4 in the longitudinal axis direction x and overlapping the tubular body 10.

[0025] The tubular body 10 preferably exists proximal to the distal end 2D of the stent 2 and distal to the proximal end 2P of the stent 2. Specifically, the tubular body 10 preferably exists from the proximal end of the distal stent section 3 to the distal end of the proximal stent section 4. In other words, as shown in FIG. 1 , it is preferable that the tubular body 10 is not present in the distal stent section 3 or the proximal stent section 4. Furthermore, it is preferable that the tubular body 10 is present only in the central stent section 5 in the longitudinal axis direction x. By not providing the tubular body 10 in the distal stent section 3 or the proximal stent section 4 in this way, the self-expansion of the distal stent section 3 and the proximal stent section 4 can be promoted, along with the self-expansion of the distal stent section 3 and the proximal stent section 4. Therefore, an in-vivo indwelling device 1 that is easy to self-expand and can obtain an appropriate expansion area in a short time can be provided.

[0026] In the longitudinal axis direction x, the sum of the length L1 of the distal stent section 3 and the length L2 of the proximal stent section 4 may be at least 1 / 2 of the length L3 of the tubular body 10, more preferably at least 3 / 5, and even more preferably at least 7 / 10. Furthermore, in the longitudinal axis direction x, the sum of the length L1 of the distal stent section 3 and the length L2 of the proximal stent section 4 may be no more than 5 times, no more than 4 times, or no more than 3 times the length L3 of the tubular body 10. By setting the length L1 of the distal stent section 3, the length L2 of the proximal stent section 4, and the length L3 of the tubular body 10 in this manner, the self-expansion of the tubular body 10 can be promoted.

[0027] 1, it is preferable that the length L1 of the distal stent section 3 and the length L2 of the proximal stent section 4 in the longitudinal axis direction x are each shorter than the length L3 of the tubular body 10. Because the tubular body 10 is longer than the distal stent section 3 and longer than the proximal stent section 4, it is easier to position the tubular body 10 in the body so as to correspond to the lesion during the procedure.

[0028] In the longitudinal axis direction x, the tubular body 10 is preferably disposed over a range of 1 / 3 or more of the total length L4 of the stent 2, and may be disposed over a range of 2 / 3 or more.

[0029] 1, in the longitudinal axis direction x, it is preferable that the length L1 of the distal stent section 3 is the same as the length L2 of the proximal stent section 4. This makes it easier for the distal stent section 3 and the proximal stent section 4 to expand at the same time, making it easier for the entire indwelling device 1 to expand evenly.

[0030] As shown in Figure 2, the distal stent section 3 is preferably longer than the proximal stent section 4 in the longitudinal direction x. That is, the length L1 of the distal stent section 3 is preferably greater than the length L2 of the proximal stent section 4 in the longitudinal direction x. During the procedure, the distal stent section 3, the portion containing the tubular body 10, and the proximal stent section 4 are exposed from the delivery device and placed in the lesion in this order, so the distal stent section 3 begins to expand before the proximal stent section 4. Because the distal stent section 3, which expands first, is longer, the expansion of the distal stent section 3 also makes it easier for the portion containing the tubular body 10 to expand.

[0031] The stent 2 may be made of any material, as long as it can withstand deformations such as diameter expansion and contraction and placement, and is biocompatible. The stent 2 preferably contains a metal. The metal is preferably an elastic metal and / or a shape-memory alloy. Preferred metals for the stent 2 include stainless steels such as SUS304 and SUS316, platinum, gold, silver, nickel, cobalt, chromium, titanium, tungsten, aluminum, magnesium, or alloys thereof. Ni-Ti alloys, Cu-Al-Ni alloys, and magnesium alloys are more preferred, with magnesium alloys being even more preferred. Using magnesium as the material for the stent 2 is expected to provide biodegradable properties, thereby shortening the duration of oral administration of antiplatelet or anticoagulant drugs. Furthermore, because magnesium is highly biodegradable in the bloodstream, the decomposition rate of magnesium can be adjusted by coating the surface of the aforementioned magnesium wire with a resin.

[0032] The stent 2 may contain a resin. The stent 2 may be made of a resin, or the stent 2 may have a stent body made of metal and a coating material made of resin that coats the surface of the stent body. The resin is not particularly limited as long as it is a biocompatible material. In addition to the materials that make up the tubular body described below, at least one of polylactic acid (PLA), poly-L-lactic acid (PLLA), polyglycolic acid (PGA), lactic acid / glycolic acid copolymer (PLGA), polycaprolactone (PCL), polydioxanone (PDS), and polyurea is preferably used, with polyurea being more preferred. By using polyurea as the coating material that coats the surface of the stent body made of metal, endothelial cells will coat the outer periphery of the indwelling device 1 within 1 to 2 months after the indwelling device 1 is placed in the body. Polyurea is preferred to maintain the structural strength of the stent 2 during this period.

[0033] The stent 2 may contain an inorganic material such as ceramic or metal oxide. The stent 2 may have a stent body made of metal and a coating material made of ceramic or metal oxide that coats the surface of the stent body.

[0034] As shown in Figure 1, the stent 2 is preferably made of wires 6 (element wires). The stent 2 is preferably formed by weaving or knitting a plurality of wires 6. The wires 6 may be twisted wires, but are preferably solid wires. Examples of the wires 6 include metal wires, resin wires, and metal wires whose surfaces are coated with resin or inorganic materials such as ceramics or metal oxides.

[0035] The diameter of the wire 6 constituting the stent 2, i.e., the wire diameter, is not particularly limited, but may be, for example, 5.0 μm or more, 6.0 μm or more, 7.0 μm or more, and is also acceptable to be 12 μm or less, 11 μm or less, or 10 μm or less.

[0036] The shape of the cross section perpendicular to the longitudinal axis direction of the wire 6 is not particularly limited, and may be circular, elliptical, polygonal, irregular, or a combination of these.

[0037] The outer diameter of the wire 6 may be the same in the longitudinal direction of the wire 6, or may vary depending on the position in the longitudinal direction of the wire 6. When the cross section of the wire 6 is not circular, the outer diameter of the wire refers to the diameter equivalent to a circle.

[0038] An antithrombogenic material may be coated on the surface of the wire 2. As the antithrombogenic material, for example, 2-methacryloyloxyethyl phosphorylcholine or a material in which 2-methoxyethyl acrylate is covalently bonded can be used.

[0039] The stent 2 is preferably tubular and has a circumferential direction p, with a plurality of arrangement patterns 7 arranged in the longitudinal direction x, the arrangement patterns 7 being repeated in the circumferential direction p. For example, FIGS. 1 and 2 illustrate an example in which the arrangement pattern 7 has a mesh structure formed by repeatedly arranging meshes 8 made of metal wires in the circumferential direction. In FIGS. 1 and 2, the arrangement pattern 7 has a ring shape as a whole due to the meshes 8 being arranged in the circumferential direction p, and a plurality of ring-shaped arrangement patterns 7 are arranged in the longitudinal direction x. The arrangement pattern 7 may be arranged over the entire circumferential direction p, or over only a portion of the circumferential direction p. While FIGS. 1 and 2 illustrate an example in which the meshes 8 are rhombic, the shape of the mesh 8 is not particularly limited and may be circular, elliptical, polygonal, irregular, or a combination thereof.

[0040] 1 and 2, the stent 2 is tubular and has a circumferential direction p, and is configured with a plurality of arrangement patterns 7 repeated in the circumferential direction p lined up in the longitudinal direction x, and it is preferable that the distal stent section 3 and the proximal stent section 4 each have three or more arrangement patterns 7. By having the distal stent section 3 and the proximal stent section 4 each have three or more arrangement patterns 7, the distal stent section 3 and the proximal stent section 4 not only function as scaffolding for fixing the position of the indwelling device 1 in the body, but also promote the self-expansion of the tubular body 10.

[0041] The number of arrangement patterns 7 that each of the distal stent section 3 and the proximal stent section 4 has is not particularly limited, but may be 3 or more, 4 or more, 5 or more, or 10 or less, 9 or less, or 8 or less.

[0042] 3, the stent 2 may be configured such that a first arrangement pattern 7A that is repeated in the circumferential direction is arranged in a plurality of rows in the longitudinal axis direction x in the distal stent section 3 and the proximal stent section 4, and a second arrangement pattern 7B that is different from the first arrangement pattern 7A and that is repeated in the circumferential direction is arranged in a plurality of rows in the longitudinal axis direction x in the central stent section 5 that overlaps with the tubular body 10. Here, the first arrangement pattern 7A and the second arrangement pattern 7B preferably differ from each other in at least one of the outer diameter of the wire rods 6 that constitute the stent 2, the cross-sectional shape of the wire rods 6 perpendicular to the longitudinal axis direction, and the mesh count (the number of meshes per inch).

[0043] In the stent 2, when the distal stent section 3, the proximal stent section 4, and the central stent section 5 each have a mesh structure section, as shown in Figure 3, it is preferable that the number of meshes in each of the distal stent section 3 and the proximal stent section 4 is greater than the number of meshes in the central stent section 5. In other words, it is preferable that the mesh 8A in the distal stent section 3 and the proximal stent section 4 is finer than the mesh 8B in the central stent section 5. By setting the mesh number in this way, it is possible to improve the vascular compression properties of the distal stent section 3 and the proximal stent section 4.

[0044] In the stent 2, when the distal stent section 3, the proximal stent section 4, and the central stent section 5 each have a mesh structure section, as shown in FIG. 4, the number of meshes in each of the distal stent section 3 and the proximal stent section 4 may be smaller than the number of meshes in the central stent section 5. That is, the mesh 8B in the central stent section 5 may be finer than the mesh 8A in the distal stent section 3 and the proximal stent section 4. By setting the mesh number in this way, it is possible to hemodynamically suppress blood flow to the aneurysm. As a result, it is possible to improve the effect of suppressing early occlusion and the effect of suppressing the recanalization rate.

[0045] In the stent 2, when the distal stent section 3, the proximal stent section 4, and the central stent section 5 each have a mesh structure section, it is preferable that, when the stent 2 is expanded, the standard deviation of the mesh area of ​​the central stent section 5 is smaller than the standard deviation of the mesh area of ​​each of the distal stent section 3 and the proximal stent section 4. This suppresses extension of the mesh in the longitudinal axis direction x in the central stent section 5, thereby enabling stable treatment at the aneurysm neck with high uniformity and independent of the blood vessel course.

[0046] The diameter of the stent 2, i.e., the length of the stent 2 in the radial direction y, is appropriately selected based on the inner diameter of the blood vessel to be treated. For example, the diameter of the stent 2 for cerebral aneurysms is preferably 2.0 mm to 5.0 mm, and more preferably 2.5 mm to 4.5 mm. The diameter of the stent 2 for aortic aneurysms is preferably 4.5 mm to 15.0 mm, and more preferably 5.0 mm to 13.0 mm.

[0047] The length of the stent 2 in the longitudinal axis direction x is appropriately selected based on the length of the lesion to be treated. For example, the length of the stent 2 for cerebral aneurysms is preferably 10 mm to 50 mm, and more preferably 12 mm to 45 mm. The length of the stent 2 for aortic aneurysms is preferably 20 mm to 120 mm, and more preferably 25 mm to 100 mm.

[0048] The tubular body 10 is preferably a tubular structure arranged along the peripheral wall of the stent 2. The tubular body 10 is preferably a tubular membrane. The tubular body 10 includes what is generally called a graft (artificial blood vessel). The tubular body 10 is preferably a cylindrical body having only one lumen. The longitudinal axis of the stent 2 and the longitudinal axis of the tubular body 10 are preferably coaxial with each other.

[0049] The tubular body 10 may be composed of a single layer or multiple layers. For example, the tubular body 10 may have an inner layer and an outer layer disposed radially outward of the inner layer. The tubular body 10 may also have an intermediate layer between the inner layer and the outer layer in the radial direction y.

[0050] As shown in Figures 1 to 5, a portion of the stent 2, for example, the central stent section 5, may be located further inward in the radial direction y than the tubular body 10. That is, the tubular body 10 may cover the stent 2 from the outer side in the radial direction y. In another embodiment, as shown in Figures 6 to 7, a portion of the stent 2, for example, the central stent section 5, may be located further outward in the radial direction y than the tubular body 10. That is, in a side view of the indwelling device 1, a portion of the stent 2 may be exposed from the tubular body 10.

[0051] 8, a portion of the stent 2, for example, the central stent portion 5, may be contained within the tubular body 10. That is, a portion of the stent 2 may be embedded within the tubular body 10. By arranging the tubular bodies 10 so as to sandwich the stent 2 in the radial direction y, it is possible to obtain the effect of suppressing thrombotic complications associated with thrombus adhesion to the wire 6 of the central stent 5.

[0052] The method for fixing the tubular body 10 to the stent 2 is not particularly limited, and examples thereof include suturing, adhesion, welding, and the like.

[0053] The tubular body 10 is preferably made of a biocompatible material, and is preferably made of a polymeric material. Examples of polymeric materials that can be used to make the tubular body 10 include polyester, polyethylene, polyethylene terephthalate, polytetrafluoroethylene, polyurethane, polyamide, nylon, collagen, and gelatin. The material that makes up the tubular body 10 preferably includes at least one selected from polyester, polyethylene terephthalate, polytetrafluoroethylene, polyurethane, polyacrylonitrile, polyamide, polylactic acid, polyglycolic acid, polyhydroxybutyrate, chitosan, and collagen. The tubular body 10 is preferably made of an elastic material so that it can expand in the radial direction y as the stent 2 expands. In particular, polytetrafluoroethylene is preferably subjected to a stretching process, which creates fine pores through stretching, thereby increasing flexibility and blood vessel compression.

[0054] The tubular body 10 may be formed into a tubular shape by a method such as extrusion molding or blow molding using a polymer material. The tubular body 10 may be a woven fabric, knitted fabric, or nonwoven fabric made of polymer fibers, a protein, or a combination thereof. Among these, the tubular body 10 is preferably a knitted fabric made of collagen fibers. The braided structure of collagen fibers allows the tubular body 10 to function as a scaffold for vascular endothelial cells during aneurysm repair. The tubular body 10 may also be a tubular sheet made of a polymer material. The sheet may be porous. Even if the above-mentioned materials are used for the tubular body 10, rapid endothelialization of the tubular body 10 may be more rapid than expected, potentially causing intimal hyperplasia within the stent 2 or a persistent inflammatory reaction in the vascular wall. Therefore, the tubular body 10 may be a combination of two or more of the above-mentioned structures, and proteins and / or drugs may be immobilized on the fiber surface. For example, by first modifying the surface of a polylactic acid substrate with polydopamine and polyethyleneimine, a tubular body 10 can be obtained in which the surface is coated by hydrophobic interactions with hydrophobic resin materials and by hydrogen bonds or coordinate bonds with metal materials or hydrophilic resin materials. Furthermore, the surface is preferably coated with collagen by electrostatic interactions. Humanized collagen type III is particularly preferred, and the combination of these materials can provide intimal hyperplasia inhibitory and anti-inflammatory properties. Alternatively, the tubular body 10 can be impregnated with antihyperplasia drugs such as rapamycin or sirolimus, or anti-inflammatory drugs such as HMG-CoA reductase inhibitors and COX-2 inhibitors for direct drug action. In this case, the drug added to the fiber is preferably processed into a fiber shape by electrospinning. The fiber diameter is not particularly limited, but may be, for example, 10 nm or more, 25 nm or more, or 50 nm or more. The fiber diameter may also be 100 nm or less, 500 nm or less, or 1000 nm or less. The voltage applied during electrospinning is not particularly limited, but for example, fibers can be obtained by producing them from a nozzle at an applied voltage of 15 to 20 kV and a flow rate of 0.12 to 0.20 ml / h. Furthermore, the fiber diameter can be adjusted by controlling the nozzle inner diameter and pressure.For example, if the nozzle diameter is 300 nm and the extrusion pressure is 0.02 MPa, fibers with a diameter of 100 nm to 500 nm can be obtained.

[0055] It is preferable that particles made of a radiopaque material are present inside the tubular body 10. This allows the position of the tubular body 10 within the body cavity to be identified under radioscopy. Hereinafter, particles made of a radiopaque material may be simply referred to as particles.

[0056] Examples of radiopaque materials include lead, barium, iodine, tungsten, gold, platinum, iridium, platinum-iridium alloy, stainless steel, titanium, cobalt-chromium alloy, palladium, tantalum, and bismuth.

[0057] The particles may be present within the tubular body 10 in a portion of the longitudinal axis direction x, but are preferably present within the tubular body 10 over the entire longitudinal axis direction x.

[0058] The particles are preferably encapsulated in the tubular body 10, and are preferably dispersed within the tubular body 10. The particles may be exposed on the surface of the tubular body 10. The particles may also cover the surface of the tubular body 10.

[0059] The particle size of the particles is not particularly limited, but may be, for example, 10.0 nm or more, 50.0 nm or more, 100.0 nm or more, or 200 nm or more. The particle size may also be 5.0 μm or less, 4.0 μm or less, 3.0 μm or less, 2.0 μm or less, or 1.0 μm or less. Here, "particle size" refers to the volume average particle size (D50) at the 50% median diameter in the particle size distribution obtained by dynamic light scattering or the like. Commercially available particles may be used, in which case the particle size listed in the catalog can be used.

[0060] A method for making particles present in the tubular body 10 includes, for example, adding particles when kneading the material (preferably the polymer material described above) that constitutes the tubular body 10 using an extruder or the like.

[0061] 9, in the indwelling device 1, one or more other wires (second wires 20) extending in the longitudinal axis direction x may be fixed to the portion of the stent 2 that overlaps with the tubular body 10 (central stent portion 5). This makes it easier to promote the expansion of the tubular body 10.

[0062] The second wire 20 is preferably arranged from the distal stent section 3 to the central stent section 5. The second wire 20 is preferably arranged from the proximal stent section 3 to the central stent section 5. Furthermore, it is preferable that one second wire 20 traverses the distal stent section 3, the central stent section 5, and the proximal stent section 4.

[0063] The second wire rod 20 is preferably linear. For the configuration of the second wire rod 20, the description of the wire rod 6 that preferably constitutes the stent 2 can be referred to.

[0064] A plurality of second wire rods 20 are preferably fixed to the stent 2. In this case, the plurality of second wire rods 20 are preferably arranged at equal intervals in the circumferential direction p.

[0065] It is preferable that the second wire rod 20 is fixed to the wire rod 6 (first wire rod 6) constituting the stent 2. As shown in FIG. 10, the second wire rod 20 may be arranged inward from the tubular body 10 in the radial direction y. Also, as shown in FIG. 11, the second wire rod 20 may be contained within the tubular body 10. Although not shown, the second wire rod 20 may be arranged outward from the tubular body 10 in the radial direction y. Although not shown, one second wire rod 20 may have a portion arranged inward from the tubular body 10 in the radial direction y and a portion arranged outward from the tubular body 10 in the radial direction y.

[0066] As shown in Figure 10, in the central stent section 5, when the stent 2 is arranged radially inward of the tubular body 10, the second wire 20 may be joined to the inner side of the wire 6 (first wire 6) in the radial direction y.

[0067] Methods for fixing the second wire 20 to the stent 2 include adhesion, fusion bonding, welding, and braiding into the wire 6 (first wire) that constitutes the stent 2.

[0068] The indwelling device 1 may have one or more radiopaque markers. This makes it possible to identify the position of the indwelling device 1, the stent 2, or the tubular body 10 within a body cavity under radioscopy. The radiopaque marker is preferably an X-ray opaque marker. Hereinafter, the radiopaque marker may be simply referred to as a marker.

[0069] The marker can be fixed to at least one of the stent 2, the wire 6, the tubular body 10, and other members of the indwelling device 1.

[0070] When the indwelling device 1 has a plurality of markers, the markers may be arranged side by side in the longitudinal axis direction x, or may be arranged side by side in the circumferential direction p.

[0071] The shape of the marker is not particularly limited, and may be a circle, an oval, a polygon, a plate, a column, a cone, a frustum, a sphere, an L-shape, a T-shape, a ring, a C-shaped cross section formed by a notch in a ring, a coil shape formed by winding a wire, or a combination of these shapes, etc. Note that Fig. 12 shows an example in which the marker 31A is in a disk shape.

[0072] The marker may contain a radiopaque substance, for which the above description of radiopaque materials can be referred to.

[0073] The marker can be fixed to the indwelling device 1 by methods such as welding, fusion bonding, adhesion, suturing, or crimping. When the marker is disposed in the distal stent section 3 and / or the proximal stent section 4, the marker is preferably fixed to the stent 2 (preferably to the wire 6) by welding. When the marker is disposed in the tubular body 10, the marker is preferably fixed to the tubular body 10 by adhesion. Examples of adhesives that can be used include acrylic adhesives and urethane adhesives.

[0074] It is preferable that the indwelling device 1 further has a radiopaque marker disposed at at least one of the distal end and the proximal end of the tubular body 10. Fig. 12 shows an example in which a radiopaque marker 31A is disposed at the distal end of the tubular body 10 and a radiopaque marker 31B is disposed at the proximal end of the tubular body 10. By providing markers at least at the distal end and the proximal end of the tubular body 10 in this way, the position of the tubular body 10 within the body can be identified, thereby enabling the procedure to be performed efficiently.

[0075] 12, a marker 31A is preferably provided at the distal end 10D of the tubular body 10, and more preferably, multiple markers 31A are provided at the distal end 10D of the tubular body 10. Also, a marker 31B is preferably provided at the proximal end 10P of the tubular body 10, and more preferably, multiple markers 31B are provided at the proximal end 10P of the tubular body 10. This makes it even easier to identify the position of the tubular body 10 within the body.

[0076] The marker 31A may be fixed to the radially outer surface of the tubular body 10, or may be fixed to the radially inner surface of the tubular body 10. The marker 31A may also penetrate the tubular body 10 in the radial direction of the tubular body 10. The marker 31A may also be embedded in the tubular body 10.

[0077] It is preferable that the indwelling device 1 further has a radiopaque marker arranged in at least one of the distal stent section 3 and the proximal stent section 4. Fig. 12 shows an example in which a radiopaque marker 32A is arranged in the distal stent section 3 and a radiopaque marker 32B is arranged in the proximal stent section 4. This makes it possible to identify the positions of the distal stent section 3 and / or the proximal stent section 4, thereby enabling the procedure to be performed efficiently.

[0078] 12, a marker 32A is preferably provided at the distal end 3D of the distal stent section 3, and more preferably, multiple markers 32A are provided at the distal end 3D of the distal stent section 3. Furthermore, a marker 32B is preferably provided at the proximal end 4P of the proximal stent section 4, and more preferably, multiple markers 32B are provided at the proximal end 4P of the proximal stent section 4. This makes it even easier to identify the position of the distal stent section 3 and / or the proximal stent section 4 in the body.

[0079] As shown in Figure 13, the tubular body 10 has a radial direction, and when the thickness of the tubular body 10 is divided into two equal parts in the radial direction into an inner portion 11 and an outer portion 12, it is preferable that the in-vivo indwelling device 1 further has a radiopaque marker disposed on the inner portion 11. Figure 13 shows an example in which markers 33A and 33B are disposed on the inner portion 11 of the tubular body 10. By disposing the markers on the inner portion 11 in this way, it becomes easier to identify the position of the tubular body 10 within the body while preventing the markers from coming into contact with the inner wall of the blood vessel. It is preferable that the markers are fixed to the inner portion 11 of the tubular body 10, as with markers 33A and 33B in Figure 13.

[0080] 13, the markers 33A and 33B are fixed to the inner surface of the tubular body 10. Although not shown, the markers 33A and 33B may be included in the inner portion 11 of the tubular body 10.

[0081] 13, the radiopaque markers are preferably arranged in the mesh 8 of the mesh structure portion of the stent 2. In other words, the radiopaque markers are preferably arranged so as not to overlap with the wire rods 6 that constitute the stent 2. [Explanation of symbols]

[0082] 1: Intravital device 2: Stent 3: Distal stent section 4: Proximal stent section 5: Central stent section 6: Wire rod 7, 7A, 7B: Array pattern 8, 8A, 8B: Mesh 10: Tubular body 11: Inner part 12:Outer part 20: Second wire 31A, 31B, 32A, 32B, 33A, 33B: Radiopaque marker L1: Length of distal stent section L2: Length of the proximal stent L3: Length of the tubular body L4: Length of the device x: longitudinal axis direction y: radial direction p: Circumferential direction

Claims

1. a stent having a longitudinal direction and a radial direction, the stent having a distal end and a proximal end in the longitudinal direction; a tubular body having a distal end and a proximal end in the longitudinal axis direction, fixed to the stent proximally and distally of the distal end, and extending in the radial direction as the stent expands; The stent has a distal stent section extending from the distal end of the stent to the distal end of the tubular body in the longitudinal axis direction, and a proximal stent section extending from the proximal end of the stent to the proximal end of the tubular body, The in-vivo indwelling device, wherein the total length of the distal stent portion and the proximal stent portion in the longitudinal axis direction is at least half the length of the tubular body.

2. 2. The in-vivo indwelling device according to claim 1, wherein the tubular body is not present in the distal stent section and the proximal stent section.

3. 3. The in-vivo indwelling device according to claim 1, wherein the length of the distal stent portion and the length of the proximal stent portion in the longitudinal axis direction are both shorter than the length of the tubular body.

4. 3. The in-vivo indwelling device according to claim 1, wherein the distal stent portion is longer than the proximal stent portion in the longitudinal direction.

5. The stent is tubular and has a circumferential direction, and is configured such that a plurality of arrangement patterns that are repeated in the circumferential direction are arranged in the longitudinal axis direction, 3. The in-vivo indwelling device according to claim 1, wherein the distal stent section and the proximal stent section each have three or more of the arrangement patterns.

6. 3. The in-vivo indwelling device according to claim 1, further comprising a radiopaque marker disposed at least at one of the distal end and the proximal end of the tubular body.

7. 3. The in-vivo indwelling device according to claim 1, further comprising a radiopaque marker disposed on at least one of the distal stent portion and the proximal stent portion.

8. 3. The in-vivo indwelling device according to claim 1 or 2, wherein the tubular body has a radial direction, and when the thickness of the tubular body is divided in the radial direction into two equal parts, an inner part and an outer part, the in-vivo indwelling device further comprises a radiopaque marker disposed in the inner part.

9. 3. The in-vivo indwelling device according to claim 1, wherein the material constituting the tubular body includes at least one selected from polyester, polyethylene terephthalate, polytetrafluoroethylene, polyurethane, polyacrylonitrile, polyamide, polylactic acid, polyglycolic acid, polyhydroxybutyrate, chitosan, and collagen.

10. 10. The in-vivo indwelling device according to claim 9, wherein particles made of a radiopaque material are present within said tubular body.

11. 3. The in-vivo indwelling device according to claim 1, which is used for treating cerebral aneurysms.

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