JP2018175776A - Covered stent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a covered stent capable of simultaneously and parallel performing treatment of avoiding growth of bump such as aneurysm, along with expansion treatment of a stenosed vessel.SOLUTION: A covered stent 100 includes: a stent body 110 formed of a cylindrical body of a mesh-like tissue using bioabsorbable fibers 112 and capable of expanding/reducing the diameter of the cylindrical body; and a cover material 120 spirally wound around the cylindrical body at an inner surface of the cylindrical body of the stent body 110. The cover material 120 is a material suitable for culturing vascular endothelial cells, and the cover material 120 is comprised of a foam, a nonwoven fabric, a thin film, and a composite thereof.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a stent for minimally treating vascular lesions such as stenoses and aneurysms, and in particular, not only dilation of stenotic vessels, which is the main use of general stents, but also aneurysm growth and the like The present invention relates to a covered stent that can be used for treatment and the like.

In the past, a stent that is a hollow tubular medical device is placed in a lesion such as a constricted part or an obstructed part produced in a lumen or body cavity in a living body such as a blood vessel, bile duct, esophagus, trachea, urethra or other organs. There is a stent placement method that maintains the lesion in a patent state.
For example, when treating ischemic heart disease, make a small incision in the patient's leg or arm artery, place the introducer sheath (introducer), and advance the guide wire through the lumen of the introducer sheath. A balloon catheter with a long hollow tube called a guide catheter (sometimes simply referred to as a catheter) inserted into the blood vessel and placed at the entrance of the coronary artery, then withdrawing the guide wire and inserting another thin guide wire in advance Is inserted into the lumen of the guide catheter, and the balloon catheter is advanced under radiography to a lesion (stenosis or occlusion) in the patient's coronary artery with the guide wire leading to position the balloon within the lesion. Inflate the balloon. This dilates the vascular lumen of the lesion and maintains the patency, thereby increasing blood flow through the vascular lumen. Then, in order to reduce the restenosis rate, a stent is placed at a balloon-expanded lesion.

The balloon may be contained in a stent and transported to the lesion, and the balloon may be expanded together with the stent to expand the blood vessel lumen of the lesion, and the balloon may be recovered to place the stent in the lesion. .
Placement of the stent in the blood vessel is performed using a catheter inserted into the blood vessel. When this stent is inserted into a blood vessel, it is attached to the catheter in a state where the outer peripheral diameter is reduced so that the stent can be inserted smoothly into the blood vessel without falling off the catheter and inserted into the blood vessel. The large diameter of the outer peripheral diameter maintains the patented state of the expanded blood vessel lumen.

  Not only dilation treatment of constricted blood vessels, which is the main use of such general stents, covered stents formed by covering the surface of a stent base material with a covering material are aneurysms with wide openings such as head and neck aneurysms. In recent years, it has attracted attention because it can be used for the treatment of blockages. In addition, the covered stent is also expected as a novel DDS (Drug Delivery System: drug delivery system) by applying a drug to the surface of the cover material and delivering it locally.

  JP 2008-194380 A (Patent Document 1) discloses such a covered stent. The covered stent disclosed in Patent Document 1 is characterized in that an expandable / contractible tubular stent base material is covered with a covering material made of extracted collagens. And this patent document 1 has the following description. The stent base material used for this covered stent can utilize any of a balloon-expandable stent and a self-expanding stent, and the length is about 5 to 80 mm, and the diameter is about 10 to 100% of the length. It is preferable that it is tubular. In addition, it is preferable to be mesh-like so as to be able to expand and contract flexibly, and in particular to be in the shape of an oblique lattice and in which the extending direction of the lattice is a spiral direction. The cover material used for this covered stent is made of extracted collagens, and the extracted collagens have high cell-growth / growth-promoting, low antigenicity, high biocompatibility, and high biodegradability. As it is a molecule, when this covered stent is implanted into a blood vessel, it can suppress the occurrence of a thrombus and can be rapidly replaced with the intravascular tissue.

JP, 2008-194380, A

  For example, in order to treat a lesion that forms a narrowing vessel and an aneurysm in a low-invasive manner, the stent avoids the narrowing procedure and prevents the blood from flowing to the aneurysm. It may be necessary to treat concurrently with a lump growth avoidance treatment that avoids lump growth. In such a case, a covered stent is preferably used. In this case, in addition to the stent base material and cover material of the cover stent being required to have performance (expansion / contraction performance) in order to suitably perform the stenosis avoidance treatment, performance (blood Flow blocking performance) is required.

However,
(1) Even if the stent base material of the covered stent disclosed in Patent Document 1 is mesh-like so that it can be flexibly expanded and contracted, the cover material does not have such flexible expansion and contraction (at least the cover material It is difficult to shrink the diameter of the covered stent and store it in the catheter, and expand the diameter of the covered stent to make the patency state of the lumen of the blood vessel clear. It may not be possible to preferably carry out a stenosis avoidance procedure to maintain (including transport to the lesion).
(2) Furthermore, even if the covering material of the covered stent disclosed in Patent Document 1 is capable of suppressing the occurrence of a thrombus and rapidly replacing it with the intravascular tissue when it is implanted in the blood vessel lumen of a lesion. Immediately after the covered stent is implanted in the blood vessel lumen, there is a possibility that the aneurysmal growth avoidance treatment can not be suitably performed because the tissue is not rapidly replaced with the intravascular tissue.

  In addition, even in the case of treating only the aneurysm growth avoiding treatment instead of treating the stenosis avoiding treatment and the aneurysm growth avoiding treatment in parallel, the catheter is stored in the catheter up to the lesion forming the aneurysm. There is no substitute for having to deliver covered stents. Therefore, since the diameter of the covered stent is reduced and stored in the catheter, the covered stent capable of the aneurysm growth avoiding treatment is required to have a dilation function (which is substantially the same as the function required for the stenosis avoiding treatment). As a result, the covered stent according to the present invention is not limited to the use of treating a stenosis avoiding treatment and a lump growth avoiding treatment in parallel.

  The present invention has been developed in view of the above-mentioned problems of the prior art, and the object of the present invention is not only the dilation treatment of constricted blood vessels but, for example, parallel growth of aneurysms and the like An object of the present invention is to provide a covered stent which can be used for treatment and the like.

In order to achieve the above object, a covered stent according to the present invention takes the following technical measures.
That is, the covered stent according to the present invention is formed by a tube of a mesh-like tissue using a wire, and the diameter of the tube can be expanded and contracted, the stent body, and the inner surface and the outer surface of the tube of the stent body. At least one of them includes a cover material spirally wound around the cylinder.

Preferably, the planar shape of the cover material before being spirally wound on the cylindrical body is a rectangle, and the rectangular shape and the angle of spirally wound are such that the diameter of the cylindrical body of the stent body is expanded or contracted It can be configured to be of possible shapes and angles.
More preferably, the cover material can be configured to be any of foam, non-woven fabric, thin film and composites thereof.

  More preferably, at least one of the wire and the cover material can be configured to be made of a bioabsorbable material.

  According to the covered stent of the present invention, for example, it can be used not only for dilation treatment of a narrowed blood vessel, but also for parallel growth of aneurysm growth and the like.

It is a general view of the diameter expansion state of the covered stent which concerns on this invention, Comprising: (A) is a general view of the covered stent 100 which hold | maintained the cover material on inner surface, (B) is the covered stent 200 which hold | maintained the cover material on the outer surface. It is a whole view. It is sectional drawing of the diameter expansion state of the covered stent which concerns on this invention, Comprising: (A) is sectional drawing of the covered stent 100 which hold | maintained the cover material on the inner surface, (B) is the covered stent 200 which held the cover material on the outer surface. FIG. It is a general view of the diameter-reduced state of the covered stent which concerns on this invention, Comprising: (A) is a general view of the covered stent 100 which hold | maintained the cover material on the inner surface, (B) is the covered stent 200 which hold | maintained the cover material on the outer surface. It is a whole view. It is an exploded view of a covered stent concerning the present invention. It is an explanatory view showing the state where the covered stent concerning the present invention was included in catheter 300. It is a figure for demonstrating the treatment method of the vascular stenosis provided with the aneurysm using the conventional stent 500. FIG. It is a figure for demonstrating the treatment method of the vascular stenosis provided with the aneurysm using the covered stent 100,200 which concerns on this invention.

Hereinafter, covered stents 100 and 200 according to the present invention will be described in detail based on the drawings.
[Configuration: Overall configuration]
As shown in FIGS. 1A, 2A, and 3A, a covered stent 100 according to the present embodiment has a mesh-like tissue using a wire (more specifically, a bioabsorbable fiber 112). A stent main body 110 which can be expanded and contracted in diameter of the cylindrical body, and a cover member 120 spirally wound around the cylindrical body on the inner surface of the cylindrical body of the stent main body 110 There is. Alternatively, as shown in FIG. 1 (B), FIG. 2 (B) and FIG. 3 (B), a covered stent 200 according to the present embodiment has a mesh-like structure using a wire (bioabsorbable fiber 112). The stent main body 110 is formed of a cylindrical body, and the diameter of the cylindrical body can be expanded and contracted, and the outer surface of the cylindrical body of the stent main body 110 is configured to include a cover material 120 spirally wound around the cylindrical body. . The covered stent according to the present invention may be a covered stent 100 and a covered stent 200 as long as the covering material 120 is spirally wound around at least one of the inner surface and the outer surface of the cylindrical body of the stent body 110. Alternatively, the cover material 120 may be spirally wound around the inner surface and the outer surface of the cylindrical body of the stent body 110.

  And since this cover material 120 is helically wound so that the diameter of the cylinder of the stent main body 110 can be expanded and contracted, and since this cover material 120 itself is formed helically, the stent main body 110 is formed. And the cover member 120 are configured to be able to expand and contract their diameters. Because of this configuration, the cylindrical diameter of the covered stent 100 composed of the stent body 110 and the cover material 120 is smaller than the inner diameter of the catheter when the diameter is reduced, and for catheter treatment when the diameter is expanded. Any suitable size can be provided. For example, the cylinder diameter of the covered stent 100 when the diameter is expanded is about 5 mm to 80 mm, preferably about 15 mm to 25 mm. Further, the length of the covered stent 100 and the density of the stitches in the stitched tissue knitted by the wire have a length and density suitable for catheter treatment.

Although the covered stent 100 and the covered stent 200 (and the covered stent in which the covering material 120 is wound on the inner surface and the outer surface) will be described in more detail below, these covered stents indicate the position where the covering material 120 is wound and Only the number (one only in the inner surface, one only in the outer surface, and two in total in the inner surface and the outer surface) may be described as a representative of the covered stent 100.
[Configuration: Stent body]
As shown in FIG. 1 to FIG. 3 and FIG. 4 (A), the stent main body 110 of the covered stent 100 is a cylinder of a mesh-like tissue using a wire (bioabsorbable fiber 112), and the cylinder The diameter of the is formed so as to be scalable. FIG. 4A is a view showing only the stent main body 110 which constitutes the covered stent 100. FIG. In FIG. 4A, the wire (bioabsorbable fiber 112) disposed on the back side of the paper surface is not shown in order to facilitate understanding of the stitches of the wire (bioabsorbable fiber 112). .

The wire constituting the stent main body 110 is not limited, but a bioabsorbable material can be adopted, and in the present embodiment, the bioabsorbable fiber 112 is adopted as the wire.
The bioabsorbable fiber 112 may be, for example, polyglycolic acid, polylactide (D, L, DL form), polycaprolactone, glycolic acid-lactide (D, L, DL form) copolymer, glycolic acid-ε-caprolactone copolymer. Polymer, lactide (D, L, DL form) -ε-caprolactone copolymer, poly (p-dioxanone), glycolic acid-lactide (D, L, DL form)-ε-caprolactone copolymer, etc. Of at least one type, and used in the form processed into any of monofilament yarn, multifilament yarn, twisting yarn, braid and the like, but is preferably used in the form of monofilament yarn.

Furthermore, the material of the bioabsorbable fiber 112 may be a biodegradable alloy. An example of such a biodegradable alloy is a magnesium-based alloy as a raw material.
The diameter of the bioabsorbable fiber 112 is about 0.001 mm to 1.5 mm, and the fiber diameter and type suitable for the catheter treatment to be applied are selected. In addition, the cross section of the bioabsorbable fiber 112 may be any shape such as a circle, an ellipse, or another variant (for example, a star), as long as the tissue in the living body is not damaged. Furthermore, the surface of the bioabsorbable fiber 112 may be subjected to a hydrophilization treatment by plasma discharge, electron beam treatment, corona discharge, ultraviolet irradiation, ozone treatment or the like. In addition, the bioabsorbable fiber 112 is a drug suitable for applying or impregnating a radiopaque material (eg, barium sulfate, gold chip, platinum chip, etc.) or a drug (eg, catheter treatment for atrial septal defect) ), And may be coated with a natural polymer such as collagen or gelatin, or a synthetic polymer such as polyvinyl alcohol or polyethylene glycol.

The stent body 110 is a braid wherein the bioabsorbable fibers 112 have multiple (e.g., eight or twelve) yarn feeders around an outer diameter silicone rubber tube (not shown) desired as a monofilament yarn, for example. It is manufactured into a braided woven fabric using a machine, or is knitted into a braided structure of cylindrical bodies of substantially the same diameter by a circular knitting machine (not shown).
[Composition: cover material]
Next, the cover material 120 wound so that the diameter of the cylindrical body of the stent body 110 can be expanded and contracted will be described with reference to FIGS. 1 to 3 and FIGS. 4 (B) and 4 (C). FIGS. 4B and 4C are views showing only the cover material 120 that constitutes the covered stent 100. FIG. 4B is an overall view of the cover material 120 alone after being spirally wound on the stent body 110, and FIG. 4C is a cover material before being spirally wound on the stent body 110. It is a figure which shows the planar shape of 120 single-piece | units.

Before the cover member 120 is spirally wound around the cylindrical body of the stent body 110, the planar shape is rectangular (three-dimensionally thin and thin rectangular parallelepiped shape) and rectangular (FIG. 4C). The width W) shown in and the angle of spirally winding (angle α shown in FIG. 4C) are shapes and angles with which the diameter of the cylindrical body of the stent body 110 can expand and contract.
As described above, the cover material 120 is knitted into a mesh-like structure of a tubular body having substantially the same diameter by the stent main body 110 made of the bioabsorbable fiber 112 as a braided fabric or a circular knitting machine (not shown). A thin, long and thin cover member 120 whose width is indicated by W on at least one of the inner surface and the outer surface of the cylindrical body which is the main shape of the stent main body 110 with respect to the stent main body 110; And helically wrap them into a single stent body 110 to complete a covered stent 100.

Thus, since the cover material 120 is helically wound so that the diameter of the cylindrical body of the stent body 110 can be expanded and contracted, and the cover material 120 itself is formed in a spiral shape, the stent body 110 and the cover material Both 120 are configured to be able to expand and contract their diameter, and as a result, the diameter of the covered stent 100 is configured to be expandable.
Furthermore, the cover material 120 is a material suitable for culturing vascular endothelial cells, and the cover material 120 is any of foam, non-woven fabric, thin film and composite of these.

Furthermore, the cover material 120 may be made of a bioabsorbable material. The bioabsorbable material adoptable to the cover material 120 is the same as the bioabsorbable fiber 112 employed as the wire, and therefore the detailed description thereof will not be repeated here.
As a material of the cover material 120, a substrate disclosed in Japanese Patent No. 3603179 including the applicant of the present application can be adopted as a material particularly suitable for culturing vascular endothelial cells. The base material used as the material of the cover material 120 is any of foams, non-wovens, thin films and composites thereof suitable for culturing vascular endothelial cells. More specifically, as described in this publication, a base material in which a foam made of a bioabsorbable material is reinforced with a reinforcing material (fibrous, non-woven, film-like) made of a bioabsorbable material is used. The cover material 120 of the covered stent 100 according to the embodiment can be employed.

  Here, the combination of the foam and the bioabsorbable material constituting the reinforcing material is optional, and in the case of a blood vessel, a lactic acid-caprolactone copolymer as a foam, in the case of an artery, polylactic acid as a reinforcing material, and in the case of veins A combination of glycolic acid can be exemplified. Furthermore, the pore size of the foam is preferably such that cells adhere properly and proliferate and do not leak when implanted as cardiovascular tissue, and the pore size is usually 1 mm or less, preferably 5 to 100 μm.

As described above, the covered stent 100 according to the present embodiment has the following features. (First feature) The covered stent 100 is formed by a tubular body of a mesh-like tissue using the bioabsorbable fiber 112 as a wire, and the stent body 110 whose diameter can be expanded and contracted, and the tubular body of the stent body 110 And a cover member 120 provided on at least one of the inner surface and the outer surface of the
(Second feature) The cover material 120 is spirally wound on the stent body 110 so that the diameter of the cylindrical body of the stent body 110 can be expanded and contracted (that is, the diameter of the entire covered stent 100 can be expanded and contracted). There is.
(Third feature) The cover material 120 is a material suitable for culturing vascular endothelial cells, and is disclosed in any of foam, non-woven fabric, thin film and composites thereof (particularly preferably disclosed in Japanese Patent No. 3603179). Base material).

The case where the covered stent 100 having such features is used for catheter treatment will be described with reference to FIGS. 5 to 7.
[Use mode]
FIG. 5 is an explanatory view showing a state in which the covered stent 100 according to the present embodiment is included in the catheter 300, and FIG. 6 is a view for explaining a method for treating a vascular stenosis having an aneurysm using the conventional stent 500. FIG. 7 is a diagram for explaining a method of treating a vascular stenosis having an aneurysm using the covered stent 100 according to the present embodiment in FIG. Here, the conventional stent 500 is a stent that is configured only with the stent body 110 of the covered stent 100 according to the present embodiment and does not have the cover material 120.

  FIG. 5 shows a state in which the entire covered stent 100 according to the present embodiment in which the tissue construction described later is completed is accommodated in the catheter 300, and the covered stent 100 is inside the catheter 300 (the space formed by the inner wall 310). The whole of is stored. The covered stent 100 is pushed out in the arrow X direction from the opening 320 of the catheter 300 at the lesion.

  First, vascular endothelial cells are cultured on the covering material 120 of the covered stent 100 before treatment. That is, the vascular endothelial cells are seeded and cultured on the cover material 120 of the covered stent 100 so that blood does not leak from the covered stent 100 (so that the blood flow to the aneurysm can be stopped). Using the material 120 as an optimal scaffold for cell growth, the covering material 120 is allowed to organize vascular endothelial cells.

Also as to the tissue construction of this vascular endothelial cell, as disclosed in the aforementioned Japanese Patent No. 3603179, as a cell to be seeded, a cell type which is almost common in cardiovascular tissue can be used, and endothelial cell, smooth Myocytes and fibroblasts can be exemplified by these two or three mixed culture cells, and mixed culture cells are used to perform tissue construction. Regarding the culture conditions of cells to be used and the method of seeding, as disclosed in the above-mentioned Japanese Patent No. 3603179, “A. Cell isolation, cell culture, cell number increase”, “B. Cell sequestration, endothelial cell purification Vascular endothelial cells were organized in the covering material 120 with reference to “C. Tissue construction” and “C.

When such tissue construction is completed, it is housed in the catheter 300 as shown in FIG. 5 and treatment is started. In the following, only matters specific to the usage mode of the covered stent 100 according to the present embodiment will be described, and general matters are the same as in the known catheter treatment, and therefore, detailed description here will be made. Will not repeat.
As shown in FIGS. 6 (A) and 7 (A), a conventional stent 500 and the present invention are used for a disease in which an aneurysm 450 is formed in a blood vessel (here, artery) 400 of a living body (here, human). The case where the covered stent 100 which concerns on embodiment is used is each demonstrated. In addition, the narrowed state and the obstructed state of the blood vessel 400 are not shown.

The catheter 300 is used to deliver the conventional stent 500 to the lesion, and the balloon is used to expand the vascular lumen of the lesion to reduce the restenosis rate. Detained.
In this case, as shown in FIG. 6 (B), the stent 500 is not provided with the cover member 120, and the stent main body is constituted only by the stent body 110. Therefore, as shown in FIG. 6 (B) As such, the blood flowing through the blood vessel 400 through the braided tissue flows to the aneurysm 450. As a result, the aneurysm 450 does not clot, and sometimes expands as shown in FIG. 6 (C). Furthermore, with the mere stent 500 without the cover material, for example, since the drug can not be carried on the cover material for avoiding restenosis (without DDS function), in the long term as shown in FIG. Thrombus formation may occur in the vascular lumen or reocclusion due to stenosis may occur.

  On the other hand, the covered stent 100 according to the present embodiment is transported to the lesion using the catheter 300, and the blood vessel lumen of the lesion is expanded by the balloon and expanded by the balloon to reduce the restenosis rate. The covered stent 100 is placed in the affected area. At this time, since the cover material 120 is spirally wound on the stent body 110 so that the diameter of the cylindrical body of the stent body 110 can expand and contract (and consequently the diameter of the entire covered stent 100 can expand and contract), The covered stent 100 can be easily included in a catheter, the covered stent 100 can be reliably transported to the lesion, and the expanded stent 100 can be placed in the balloon-expanded lesion, so that the lesion can be included. It is possible to maintain the expanded state of the vascular lumen of the part.

  In this case, as shown in FIG. 7B, since the vascular endothelial cells are organized in the covering material 120 of the covered stent 100, the blood flowing in the blood vessel 400 as shown in FIG. 7B. Does not flow to the aneurysm 450. As a result, the aneurysm 450 clots. Furthermore, since the cover material 120 of the covered stent 100 can also carry, for example, an agent for avoiding restenosis on the cover material (with DDS function), as shown in FIG. It is also possible to suppress the formation of a thrombus in the vascular lumen and the occurrence of reocclusion due to a stenosis.

As described above, the covered stent 100 according to the present embodiment can be used not only for dilation treatment of a narrowed blood vessel, but also, for example, for aneurysm growth avoidance treatment and the like simultaneously in parallel.
It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is indicated not by the above description but by the claims, and is intended to include all the modifications within the meaning and scope equivalent to the claims.

  The present invention relates to a stent for treating a vascular lesion such as a stenosis or an aneurysm with low invasiveness, and is used not only for dilation of a stenosed blood vessel, but also, for example, for parallel growth of aneurysm growth and the like. It is particularly preferred for covered stents that can be

100, 200 covered stent 110 stent body 112 (constituting stent body) bioabsorbable fiber 120 covering material 300 catheter 400 blood vessel (arterial)
450 aneurysm 500 conventional stent

Claims (4)

A stent body which is formed by a tubular body of a wire-like structure using a wire, and the diameter of the tubular body can be expanded and contracted;
A covered stent, comprising: a cover material spirally wound around the cylindrical body on at least one of the inner surface and the outer surface of the cylindrical body of the stent body. The planar shape of the cover material before being helically wound around the cylinder is a rectangle,
The covered stent according to claim 1, wherein the rectangular shape and the helically wound angle are a shape and an angle which can expand and contract the diameter of the cylindrical body of the stent body.   The covered stent according to claim 1 or 2, wherein the cover material is any of foam, non-woven fabric, thin film and composites thereof.   The covered stent according to any one of claims 1 to 3, wherein at least one of the wire and the cover material is made of a bioabsorbable material.